Seraphinite Properties

The mica inclusions give the stone wonderful chatoyancy. The inclusions grow at different lengths, the longer ones give that feather appearance. Other times you get shorter growth patterns in rows that give the mystic forest appearance. The radial growth patterns in this stone are more highly sought after and make for beautiful designs in cabochons.

Finding Seraphinite

Although seraphinite is getting rather scarce to find, it is still available for sale at shows and online. Most of the time you can easily see what you’re getting, as the patterns will be quite visible on the outside. If you are looking for certain patterns and a higher grade, buying pre-cut slabs is the way to go. If you have never cut seraphinite before, know there are some pitfalls with this material. It’s soft and can easily break in the trimming or cabbing process. It also has varying hardnesses, so it can tend to undercut, as well as easily chip on the edges.

Cutting to Enhance the Patterns

When getting started on cutting slabs, there is a general direction to cut. Most of the time you will see radial or partial radial sprays at the bottom portion of the stone. That will give you a grasp of what is top and bottom, so you can cut north to south for your slabs. This will yield the best chatoyant patterns in the stone. I would also suggest cutting your slabs a slight bit thicker than the average stone because of its softness.

This gives you greater odds against it breaking in the cabbing process. Once your slabs are cut, many times you will get two predominant patterns for design. The top portion usually has smaller feather patterns that are tight together. The bottom portion will give you more radial sprays and longer feathery designs. Both sections are great to design cabs with but remember that the solid green areas are harder than the mica inclusions, and will tend to undercut. The lighter the color, the softer that portion.

Cabbing Seraphinite

Once your preforms are trimmed out and you are ready to cab, I would suggest a different routine than cabbing agates or jaspers. I like to start on a worn 80-grit steel wheel, or a 140-grit soft resin, as this material tends to grind away super easily and quickly. Use a soft touch to shape your outside design, then move to a 140-grit or even the 280-grit soft resin wheel to dome the top and clean up your edges and girdle on the cab.

Remember, the lighter the color, the softer it is, so beware when trying to cab thin cabs or long pointy cabs, it can break easily!

Once you have completed shaping and doming the cab on the 280-grit wheel, stop and dry it off thoroughly and be sure you have removed all the scratches by this point. With the mica inclusions running in a certain direction, you will easily see if there are any scratches, as they will stand out going against the feathery sprays.

From this point, start polishing gently on the 600-grit wheel, trying not to put too much pressure on the surface to alleviate any unwanted undercutting. Continue to the 1200 grit wheel and end on either the 3k grit or 8k grit wheel. At this point, it will give you a nice glossy finish where no added polishing compounds are needed.

This story about seraphinite previously appeared in Rock & Gem magazine. Click here to subscribe. Story by Russ Kaniuth.

The post Seraphinite – What to Cut first appeared on Rock & Gem Magazine.

Opal is a well-known example of a mineral whose color is caused by a physical phenomenon called “diffraction.” Other phenomena include iridescence, a rainbow effect seen in iris quartz and pearls; chatoyancy, which we see in cat’s-eye stones and some malachite; asterism, which is displayed in star stones; aventurescence, as seen in aventurine quartz and sunstones; adularescence, seen in moonstone; and play of color, or the alexandrite effect, seen in the alexandrite variety of chrysoberyl and some garnets. In every one of these groups, the cause of the color is related to some internal physical structure and not a metallic impurity or element in the mineral’s structure.

Opal Color

For centuries, people tried to explain the play of color seen in many opals. Finally, in the 1960s, we developed equipment that could actually see the internal structure of opal. It revealed a very orderly arrangement of submicroscopic spherules of silica. These spherules and the spaces between them acted as a diffraction grating, spreading light into its various colors. The sizes of these spherules and the angle the light struck them, coupled with the viewer’s angle, determined which color wavelengths were canceled and which ones were reflected. Diffraction of light results in opal’s play of color.

Labradorite Color

A more common mineral that gets its play of color from diffraction is the feldspar mineral labradorite. This mineral can develop in huge formations, resulting in outcrops that give off flashes of color.

Labradorite crystallizes in thin wafers in parallel layers that repeat to form a diffraction grating. This has the effect of separating light into its colors, giving labradorite a play of color that depends, in part, on the angle of the source of light. The thickness of each crystal and each cluster of crystals in their parallel layers also affect which color is seen. Labradorite can flash bronze, blue, green, and in some cases, red or violet in an overall groundmass of gray to blue. It is thought the gray color of the groundmass is due to the scattering of light by the internal structure.

Play of Color

Another attractive feldspar mineral is adularia. Like labradorite, it develops as thin crystals that line up in parallel arrangement and act as a diffraction grating. But adularia does not show a play of color. The twinned arrangement of the crystals simply scatters light. While it can also be shades of gray, pink, peach, green and brown, it is best known for a bluish-white color that is reminiscent of the moon.

Properly cut adularia gives off a cloudy sheen that seems to float throughout the polished stone. We give this lovely form of adularia the name “moonstone.”

Why does adularia have little color, while labradorite is a riot of color? Minerals color variations are because of minor variations in the refractive index of the labradorite crystals involved. In adularia, the refractive indices of the crystals are virtually the same.

Iridescence

Iridescence is described as a play of changing colors on a surface of a mineral. A prime example is the look of oil spread over the surface of water. The oil particles have a different refractive index than the water, and this physical difference results in a play of color.

The most common example of this phenomenon is called “peacock ore”, which is actually the mineral bornite (copper sulfide). A freshly broken surface of bornite quickly oxidizes, forming a thin oxide mineral layer whose refractive index differs from bornite’s and creates a play of color. More subdued examples of this iridescence are seen on some crystal surfaces of pyrite, cuprite, chalcopyrite and hematite.

Pearl Iridescence

Iridescence is what gives pearls their soft, moonlike luster, called “orient.” Pearls are made up of layer upon layer of microscopic crystals of hexagonal aragonite. The refractive indexes of these layers are the same. Colored and black pearls result from inclusions that get into the pearl’s structure.

Mother of Pearl’s lovely shimmer, or glow, comes from the interior lining of shells, which is made up of two different substances: the calcium carbonate mineral aragonite, which forms microscopic hexagonal crystals, and conchiolin, a fibrous protein that forms in layers in parallel arrangement. The parallel fibers of the conchiolin are the key to creating the iridescence we see in mother of pearl, also called “nacre.”

Chatoyancy

When the fibers of a mineral develop in a parallel arrangement, they impart a silky shimmer or glow of light, called chatoyancy, that can be very appealing. You can expect to see this shimmer in a range of minerals. Asbestos is a very common example. When the asbestos is invaded by silica, it can form what we normally call tiger’s-eye, which is a very useful chatoyant gemstone with a silky luster. The invading silica negates the hazard we normally associate with asbestos.

Iridescence Within Stain Spar

One variety of gypsum, called stain spar, also shows iridescence, or glimmer of light. The mineral looks like silk cloth, whose fibers are also arranged in a tightly woven, parallel structure. Another example of iridescence is seen in some malachite. This copper carbonate usually crystallizes in tightly packed needles, which grow in slightly diverging radiating masses. When freshly broken, these near-parallel fibers give off a shimmering green color.

Asterism is seen in minerals like diopside, gem corundum, some moonstones, and several others. In these species, included fibrous crystals of the mineral rutile, in an intersecting arrangement, reflect light in a six-rayed star pattern. This physical phenomenon is what creates rare star sapphires and rubies, which are very valuable varieties.

Cat’s-eye gems exhibit chatoyancy, as well as a single, bright, linear reflection from tightly packed parallel fibers of a second mineral. Lapidaries give these gemstones a slight to strong dome and orient them so that the included mineral, often rutile or tourmaline, runs straight across the curved surface to form a single bright line, much like the vertical iris in a cat’s eye. It is important to know that these included needle crystals are all oriented along just one of the several growth axes of the hexagonal corundum stone.

Hexagonal Minerals

Hexagonal minerals like ruby and sapphire develop along four axes: one vertical “C” axis, from which three axes develop at right angles to the “C” axis, 60º from each other. For a star gem to form, the included mineral orients along the two arms of each horizontal axis to create a six-rayed star.

Chatoyancy is also seen in the cubic mineral gem garnet. The difference is that garnets form in the cubic system so the “star” forms from needle crystals that have oriented along the two horizontal axes that make up the cube form. Only two axes extend away from the single vertical axis, so the four arms of these axes with their parallel, included needles can orient to form a four-rayed star.

Understanding Aventurescence

Aventurescence is another physical phenomenon that involves inclusions. In this case, the inclusions are usually large enough to be visible and are scattered throughout the crystal mass, rather than oriented in a particular alignment. These scattered inclusions act as reflectors that scatter the light entering the host mineral.

An intriguing example of this is the manmade material called “goldstone”, which is glass with copper inclusions that give the glass a bright reddish-gold color.

Aventurescence is named for a quartz variety called aventurine, which is a lovely green color thanks to included chrome mica. These tiny, green flakes, or spangles, are scattered throughout the quartz, giving it a diffused green color of varying intensity that is very attractive.

The most attractive gem that falls into this category is the feldspar variety sunstone. This very lovely gem is found in several places in Oregon and shows a fine orange to red color due to included copper diffused throughout the gem. In some examples, the copper orients within the feldspar so that wisps and feathers of color are prominent in the gem. Sunstone claims in Oregon are occasionally opened to collectors for a fee.

Alexandrite Effect

Finally, the alexandrite effect is seen in very few minerals whose color is based on the type of light source. The chrysoberyl variety alexandrite is the obvious example.

Alexandrite has a light absorption band that, in sunlight, can split light into two different transmission areas. Under sunlight and fluorescent light, some of the blue wavelengths are absorbed, so green becomes dominant. When seen under in incandescent light, alexandrite is red.

As you collect colorful minerals, be aware that not all of them owe their color to a trace element inclusion. This is another area of interest you can pursue as you enjoy our wonderful hobby.

This story about what gives minerals color appeared in Rock & Gem magazine. Click here to subscribe. Story by Bob Jones.

The post What Gives Minerals Color? first appeared on Rock & Gem Magazine.

Although most people know this material for its beautiful blue color, it also can be found in pink and violet. Dumortierite can be found in various places across the globe, and at times, has been mistaken for sodalite, or lapis lazuli. Some variations that have gorgeous fibrous dumortierite sprays inside quartz crystals are rare. These tend to be very small pieces, usually ranging from one to five carats. Dumortierite is a good material for lapidary beginners to get hands-on experience. It’s available almost anywhere rocks are sold in a good variety of colors and patterns. It’s fairly hard, usually about seven to eight on the Mohs scale. It also cuts fairly easily.

Tips for Buying Dumortierite

When buying Dumortierite rough, the colors usually show on the outside, but it can have a thin brown rind that can be chipped away to expose the inner color. Many times the blues can be mottled with a lot of white. If a certain hue of blue or continual color throughout is needed, it’s best to buy slabs to be certain.

Cutting Rough Dumortierite

When starting out cutting rough, there is no certain direction to load the saw. This is helpful so that it can be loaded in a way that best fits the vice and yield the most material by cutting straight across the entire stone in one direction. Once the slabs are cut, there generally aren’t many fractures in this material. However, it’s always best to bench test before marking up the slabs for preform designs. Either flex the slab in hand to see if it’s stable or lightly tap it against the workbench or ground to see if there are any hidden fractures. This helps to avoid breaking while in the middle of trimming out cab shapes.

Cabbing Dumortierite

Once the preforms are cut and ready for cabbing, be sure to have a dry towel or canned air available to check for scratches along the way. Since towels get damp in a hurry and canned air can start getting expensive, one suggestion is to get a five-gallon air tank with a spray nozzle. It can be continually filled up by a personal air compressor or by a nearby gas station and it will last for quite a while.

Dumortierite tends to quickly show heavy white marks if scratches are still present. I suggest starting on an 80-grit steel wheel to shape and dome cabs and moving to either a 60-grit soft resin wheel or 140 soft resin. This material is fairly hard, so it will take a bit of time to smooth it out and remove all the scratches from the 80-grit wheel. Be sure to dry off occasionally and see if any white scratches are showing.

From this point, move on to the 280-grit soft resin wheel. A white or pale blue haze across the cab is to be expected, but not scratches. Make sure no scratches exist before moving forward. From this point, it’s fair routine to continue cabbing to the 600 grit, all the way up to the 14k grit soft resin wheels.

Finishing Gloss

A 50k grit polishing wheel works great to get an added high-luster gloss. Unless going slow in short increments, it’s not suggested to use polishing compounds on this material. Also, be sure not to allow the material to heat up too much. It can tend to fracture with heat.

This story about dumortierite previously appeared in Rock & Gem magazine. Click here to subscribe. Story by Russ Kaniuth.

The post Dumortierite: What to Cut first appeared on Rock & Gem Magazine.

Sapphire

One of the official state gemstones of Montana, sapphires hold a special place in the Treasure State where they are readily found. Sapphires and rubies are both corundum, an aluminum oxide mineral typically found in crystalline form. The only difference between the two is the presence of chromium. If the corundum is red, it’s ruby. Otherwise, it’s always a sapphire.

One of the most desired types of gemstones, the most well-known sapphire hue is deep blue, but these gemstones are found in pink, green, violet, orange, purple and even brown. When they’re not blue, they’re referred to as fancy sapphires. These colors are because of the varying degrees of chromium, titanium oxide and iron within the stones. Sapphires also possess a trait called asterism where needle-like inclusions create the appearance of a six or twelve-patterned star. Beyond this unique characteristic appreciated by faceters, sapphires have a Mohs Amy Grisak; Getty Images/Science Photo Library value of nine, just below a diamond, making them extremely durable and an excellent choice for jewelry.

Tiger’s Eye

This distinct gem has a long history of fending off the “evil eye,” with its resemblance to a cat’s eye. In gemology, this trait is called chatoyancy, a French term meaning “shining like a cat’s eye.” When there are crocidolite (blue asbestos) fibers within cabochon-cut gemstones running parallel to each other, the rounded surface allows the light to reflect in a way that gives the tiger’s eye its signature look. Originally, scientists thought this phenomenon occurred when the crocidolite within the stone was changed by iron oxide and replaced with silica. But even though the coloration comes from this process, some researchers believe it’s actually crocidolite inclusions within columns of quartz within the stone that form the distinct paralleling nature.

Regardless of how it formed, tiger’s eye is a favorite gem for tumbling and with a Mohs value of seven, it’s a versatile stone for a multitude of uses. While it’s a ubiquitous stone these days, in the 1870s a single carat of tiger’s eye was worth an ounce of gold.

Unakite

Unakite is a terrific example of when a gemstone is a true rock as this beautiful pink and green specimen is a composite of metamorphic rocks including orthoclase, epidote and milky quartz. It’s formed during hydrothermal metamorphosis when the epidote replaces the silicate minerals, primarily plagioclase, within the granite. The epidote is green within unakite, while the pink orthoclase feldspar and quartz create the colorful speckling.

First found in the Unakas Mountains of Western North Carolina and Eastern Tennessee, it’s sometimes found in the rivers of the region, along with the beaches of Lake Superior where glaciers deposited the metamorphic rocks. With a Mohs rating of six to seven, unakite is among the types of gemstones that tumble well. It has been used to make small sculptures or is cut for jewelry. As eye-catching as it is, unakite is also valuable in construction on many levels, including being used as trim along the front steps of the south entrance of the Smithsonian National Museum of Natural History. It is also sometimes used less visibly as crushed stone in highway construction.

Vesuvianite

Sometimes called idocrase, vesuvianite was originally found along Mount Vesuvius in Italy, which buried the nearby inhabitants of the city of Vesuvius on August 24 in 79 AD, ironically during the festival of Vulcanalia, the god of fire. In the world of gem cutting, vesuvianite often refers to the rough stone, while the faceted gems are called idocrase.

Regardless of the name, this is a calcium-aluminum-silicate mineral that forms in a tetragonal structure. Its most popular colorations range from yellowish green to brownish or olive green, although there is a blue version called cyprine that derives its color from trace amounts of copper. With a Mohs value of six, vesuvianite isn’t a very hard stone and is often used for larger jewelry and sculptures. In its green coloration, it’s sometimes mistaken for other types of gemstones like peridot, although vesuvianite is far rarer.

White Topaz

While topaz is found in practically the entire color range, the white topaz is the clear version and boasts a similar appearance to a diamond. Outside of cost, there are distinct differences between the two types of gemstones. Topazes and diamonds are closely alike in clarity and color, but brilliance is where diamonds shine. Hardness is another determining factor. Diamonds reign supreme rating at Mohs 10, while topazes register as a Mohs eight, considerably less durable with a greater risk of scratching.

Topaz is created when water and magma react during the metamorphic process creating pegmatite featuring natural topaz that is typically initially clear. While the wide variety of colors is because of impurities, such as chromium replacing the aluminum within the stone, white topaz is the gem in its purest form. Specific hues are also created with heat, irradiation or the application of metal oxides to enhance colors. Topaz also exhibits pleochroism where the gem exhibits different colors depending on its angle, although the white topaz tends to remain consistent in its coloration.

Xenotime

On occasion, there are types of gemstones cut from this rare earth mineral, often found in yellowish-orange to reddish-brown hues, although high enough quality stones to facet are rare.

Like topaz, xenotime is found in pegmatite formations, as well as igneous rock and gneiss. Uranium and thorium are often found within this stone, creating natural radioactivity, although it is more commonly seen as a source for the transition metal yttrium, which is used as an alloy in the production of camera lenses and lasers. Its name is derived from the Greek terms for “vain” and “honor” in an early scientist’s snarky rebuke of another. Initially, Swedish chemist Jöns Jacob Berzelius believed he discovered a new element within the xenotime. This turned out to be the already known yttrium, which prompted mineralogist François Sulpice Beudant to throw down a bit of shade on the claim.

Yellow Kunzite

True gemologists might shudder at the inclusion of yellow kunzite in this types of gemstones list, but it’s an example of when marketing can be misguided. As a rule, kunzite is a pink to light purple variety of spodumene, a lithium-rich mineral found, once again, in pegmatite formations. Manganese gives kunzite those attractive colors. When the gem is yellow, it’s typically just called yellow spodumene. The name change might be a matter of one word sounding more appealing than the other, but it is still misleading as kunzite implies a specific hue. With a Mohs value of six and a half to seven, it is not a very durable gemstone, but it’s possible to find specimens of 20 carats or more. Spodumene, in general, is an important source of lithium, which is critical for car batteries, phones and medicine. It is mined in Afghanistan, Pakistan, California, North Carolina and South Dakota.

Zircon

Not to be confused with the synthetic cubic zirconia, zircon earned its place as a popular gemstone 2000 years ago. Found in sand and as part of many of the rocks throughout the world, zircon is one of the oldest minerals on earth. Because of its uranium content, scientists in Australia dated it back 4.4 million years. Not all zircons are radioactive, but those that are can be heat-treated to stabilize the integrity of the stone by slowing the degradation of the crystalline structure. In their natural form, zircons are found in colors ranging from clear to yellow, green, purple, brown and grays, which are typically caused because of radiation or impurities. Blue zircons, which have been popular since Victorian times, are created through heat treatments.

This story about types of gemstones by letter appeared in Rock & Gem magazine. Click here to subscribe. Story by Amy Grisak.

The post Types of Gemstones By Letter (S-Z) first appeared on Rock & Gem Magazine.

This is the first in a three-part series also covering types of gemstones with the letters J to R and types of gemstones with the letters S to Z.

What is a Gemstone? The definition of a gemstone isn’t quite as precise as the faceted beauties it describes. In general, when minerals, and sometimes organic materials such as amber, are cut and polished to create jewelry, we call them gemstones. There are nuances and outliers because some types of gemstones are too delicate to be worn, but most people in the gem world accept this general concept. To further clarify, types of gemstones are divided into “precious and semi-precious” stones with only diamonds, emeralds, sapphires and rubies encompassing the precious category. Everything else falls into the semi-precious zone, although this doesn’t necessarily imply inherent modern value or desirable characteristics. Regardless of the classification, there’s no question that when we can bring out the inherent beauty within these stones, it is something to be truly prized.

Agate

Agate is a silica-based mineral and is a popular semiprecious stone because of its attractive coloration and banding. Reportedly discovered by Greek philosopher Theophrastus roughly 2500 years ago, early people throughout the Middle East, Russia, and Greece used agates to create ornaments. According to research by the Bureau of American Ethnology, Indigenous People utilized them in much the same way.

Agate is a chalcedony, which is a type of cryptocrystalline quartz. Like many stones in this category, it’s created when groundwater seeps into the igneous rock where silica deposits form concentric layers within the rock cavities and crevices to create the telltale banded patterns.

The wide variety of colors, ranging from brown, black, white, red, gray, pink and yellow, are because of impurities in the groundwater. With a seven on the Mohs rating, agates are on the upper end of the hardness scale. This makes this translucent stone a favorite for rock tumbling. It’s often used for jewelry as well.

Bloodstone

An opaque, dark green type of gemstone, bloodstone features distinctive orange to scarlet red splatters that look like blood at first glance. This is the telltale signature of this traditional birthstone for March. The more modern birthstone choice is aquamarine.

Bloodstone is also called heliotrope, a name derived from the Greek helio meaning sun and tropos meaning toward the sun. If you garden, you’re familiar with heliotrope plants that turn toward the sun as they grow. This name indicates how the stone reflects the light. Along with legends of healing powers, bloodstone is also known as a protective stone. People will often wear or carry bloodstones to keep threats at bay.

The minerals chlorite and amphibole are responsible for the deep green coloration while iron oxide inclusions create the blood-red speckling.

Carnelian

Carnelian is one of the least expensive chalcedonies, the translucent yellow-orange to rich amber or even reddish-brown gems darken when heat treated. This includes the heat of the sun, so it’s best to keep your stone out of the sun to keep the color true. Iron is responsible for the red coloration and it’s what oxidizes and deepens when exposed to heat.

Carnelian is sometimes confused with jasper, although jasper is a type of gemstone that is typically a deep red and is opaque, rather than translucent. Plus, jasper often exhibits banding patterns on its surface appearance.

Carnelian is found throughout the world with some of the highest quality stones found in Scotland, Brazil and Washington State.

Even though it’s relatively inexpensive, many so-called carnelians are dyed and heat-treated agates. To determine if a carnelian is real, hold it up to the light. If it’s a natural carnelian, it looks cloudy. If it’s a heat-treated agate, it will most likely show striping.

Dumortierite

Although colors range from brown, green, and the rarer violet and pink, the eye-catching denim blue of this type of gemstone is probably the most popular with gemstone enthusiasts.

An aluminum boro-silicate mineral, dumortierite occurs in regions of high metamorphic activity that are also rich in aluminum and boron. Manganese, iron, and sometimes zinc inclusions, are responsible for the blue coloration.

Dumortierite was first described in 1881 after being found in the French Alps. It was named for the French paleontologist, Eugene Dumortier.

Dumortierite has a glassy (vitreous) luster. Its fibrous nature creates fine, almost hair-like radial crystals within the structure. The blue variation is sometimes mistaken for lapis lazuli, but dumortierite is typically a deeper blue or violet, plus lapis lazuli sports white or gold metallic flecks because of the pyrite within it.

Dumortierite quartz is quartz with inclusions of dumortierite.

Emerald

The birthstone for May, emeralds are a type of gemstone that earns their place as an adjective to describe a particularly intense green. The name is derived from the Greek word smaragdos, meaning green stone.

Created in metamorphic rocks when hot magma flowed over and through the crevices of limestone and shale, emeralds are a beryllium aluminum silicate. Although emeralds are a type of beryl, not all beryls are emeralds. While green beryl is still green, it’s distinctly lighter.

Chromium oxide is responsible for the emerald’s deep green. Other gems, such as peridot and tsavorite garnets, are also found in green hues but not with the same vibrancy. Registering 7-8.5 on the Mohs hardness scale and forming in hexagonal crystals, emeralds are long favorites for precious jewelry, but fakes abound. To determine authenticity, inspect the stone with a 10X loop. Flaws and inclusions, particularly a small crystal within the stone, indicate a natural emerald. Air bubbles or even a “too perfect” stone are tell-tale signs that it is not real.

Fluorite

Made of calcium fluoride, pure fluorite is colorless, yet samples are commonly found in shades of purple, golden-yellow, green, blue, pink and brown. These types of gemstones are translucent to nearly transparent with attractive banding. The term “fluorescence” became part of the terminology when physicist Sir George Gabriel Stokes was working with fluorite in 1852. Although fluorescence doesn’t consistently occur, fluorite is known to glow when there is the presence of uranium, yttrium and other rare earth elements. It often emits blue, although yellow, green, white and red shades are possible.

Also called fluorspar, it’s been produced in Illinois since the 1800s and is the state mineral. Often forming in cubic crystals, it is popular for jewelry but has a wide number of commercial applications ranging from an ingredient in ceramics to a flux used in refining metals.

Garnet

Many people picture garnets as red stones, but these types of gemstones are also found in shades of orange, pinkish-orange, green, reddish-purple, colorless and even blue and green, albeit these last two are rarer.

Garnets are formed when aluminum-laden sedimentary rock is metamorphosed. Garnets are one of the most widespread types of gemstones throughout the world. While the bulk of garnets is mined for industrial applications, it’s one of the oldest known gemstones and has been used for ornamental purposes for 5000 years. Historical evidence shows stones within the necklaces of pharaohs. Garnet signet rings were used by Roman leaders to seal documents.

Sometimes mistaken for a ruby, garnets are usually a darker red with brownish tones. When it’s held up to the light, yellow bands are often visible in a garnet while a ruby will be clear.

Hematite

Consisting of 70 percent iron, hematite is one of the primary ores of iron. Fortunately, it is one of the most abundant minerals on Earth. According to NASA, it’s also the most abundant mineral on Mars. The iron-rich environment is why Mars is dubbed the “red planet.”

Named as far back as 300-325 BCE, hematite is derived from the Greek haima, meaning blood. These types of gemstones are found in colors ranging from rust-red, brown, steel-gray to black, it always leaves a red streak when scratched on a scratchpad.

The distinct reddish hue has been used in artwork from the earliest cave paintings. It was a key pigment for Renaissance artists creating paintings with canvas and oil in the Middle Ages. Besides its importance as an ore for iron and in art, it effectively stops radiation making it useful in shielding applications. Plus, it creates a beautiful tumbled stone for those who love to collect them.

Iolite

This beautiful violet-blue stone was the secret to the Vikings’ success in crossing the ocean as they looked through a thin iolite specimen to determine the position of the sun on cloudy days. The key to this unique quality is called pleochroism where different colors are visible at different angles. For example, a piece of iolite may have the classic violet-blue hue on one side, but when it’s turned over, it appears yellow or clear.

A silicate of aluminum, iron and magnesium, iolite (also known as the mineral cordierite) is created in metamorphic and igneous rock formations. Derived from the Greek word ios meaning violet, some iolite is blue enough to look like a sapphire. Some speculate this quality is because of the presence of titanium, although iolites are easily distinguishable because of pleochroism.

This story about types of gemstones appeared in Rock & Gem magazine. Click here to subscribe. Story by Amy Grisak.

The post Types of Gemstones By Letter (A-I) first appeared on Rock & Gem Magazine.

Starting a Rock Store

Isobel Medley was an only child and was raised in the early 1920s on a prairie farm in Carberry, Manitoba. She attended a one-room school with one teacher for first through 12th-grade students. Isobel developed a strong interest in rocks and geology in those formative years. She eventually moved to Vancouver, British Columbia. In 1945 she married Al, for whom she waited eight years for his return from the War. She became the mother of three children while studying geology. Her love of rocks ultimately inspired her to open a rock store.

The Fraser Rock Shop opened in 1960 and it became the place her daughter Velma spent most of her childhood every day after school. Velma holds many fond memories of her experiences there. For instance, the original shop was located next to a Chinese market – one that Velma frequented when the fresh produce was being delivered. She remembers the shop had an apartment upstairs and she often played with children who lived there.

Quickly though, the shop grew and needed more space. Isobel had visions of a larger shop and space to teach classes. Velma recalls that this move, also on Fraser Street, brought the shop closer to her middle and high school. Growing up in a rock shop, Velma developed skills that helped her throughout her life – listening, providing for each customer, public speaking, asking questions and developing relationships that lead to lasting clients. In those years, Velma didn’t realize just what a skilled lapidary her mother was.

Isobel was a lifelong learner and pursued lapidary skills that reflected her expertise and experience, and Velma learned those same skills.

A Family Affair

The Fraser Rock Shop may have been Isobel’s brainchild, but it was really a family affair. Velma recalls her father Al being an active part of shop operations. He was a career business agent and traveled during the week, but on weekends he was involved in cutting larger rocks — Brazilian agates, jades and petrified woods to name a few. Eventually, their mutual interest led Al to purchase a jade mine with a partner. Helicopters were needed to fly to the Birkenhead Jade Mine in the interior of British Columbia where huge, on-site saws were used by her father to cut pieces of jade which were later sold in the rock store.

Velma recalls that family vacations included spending time rock hunting. “It didn’t matter what direction we were traveling; we were always looking for rocks,” Velma explained. She still has a jar of opals she collected in Mexico on a family adventure. Trips also provided insights into how stonework was done in other parts of the world. For example, Velma remembers antiquated tools in use in Mexico and a stunning European trip where they observed rocks being cut by lapidary artists lying on their stomachs.

Rock Store Adventures

Growing up in the rock shop seemed natural to Velma. She didn’t realize how uniquely special it was until high school. Velma had many wonderful experiences working alongside her mom. For instance, she recalls her mom announcing her participation in a local children’s television program called “Show and Tell.” Her mom thought it would be a great experience for her and suggested she speak about thunder eggs.

Thundereggs are found in Oregon and are formed in rhyolite lava. Customers to the shop found them to be interesting – and would choose one to cut with a diamond blade saw to reveal their internal patterns and colors. “I was feeling mortified, scared and nervous,” Velma said. “Mom stayed focused on the positives and I being obedient and not wanting to let her down, agreed to participate.” While Velma doesn’t remember the filming beyond the gentleman who took her through it, the experience was an opportunity to learn and grow.

Another time Velma recalled waiting on a young, handsome man with curly blond hair. He wanted to have a special pendant made for his fiancé at the time. Her mother cut and polished the stone, setting it to his preselected settings. Later they learned that this young man was the Canadian musician Terry Jacks, famous for the song Seasons in the Sun.

Developing Clients

Slowly, Velma developed clients of her own. She worked for a visually impaired gentleman who paid her to polish the stones he would give as gifts. Velma’s mother tasked her with teaching a legally blind girl to shape cabochons on the grinder. This was a good challenge because it’s easy for a sighted person to grind away a layer or two of skin!

“There was a lot of activity in the rock shop, so it was fun being there,” Velma said. Not only were there classes for adults and youth, but often people came in and rented equipment by the hour. People renting equipment for .35 cents an hour always had her mom as a resource while polishing and cutting stones. The shop was a hub for rock club events, students of all ages and anyone interested in learning about rocks.

Lifetime Achievements

“I do admire the sense of achievement my parents shared throughout their lives,” Velma declared. “The joy of work for us, I think, could be attributed to all the wonderful people we met, helped, taught and encouraged.”

Velma went on to say that over the years, they had belonged to a couple of different rock clubs building life-long friendships that spanned fun annual gatherings, food, games, music and memories which of course included attending rock shows!

“Rockhounds come in all ages,” she added. “Even from prairie farms.”

Rocks for Sale

While Velma was living in Alberta, her parents sold the rock store in the mid-1980s, (or so she thought) only to fully realize after their deaths that they had retained their extensive collection of finished jewelry, cut and uncut stones. Recently, Velma has been working to sell the entire collection.

This story about growing up in a rock store appeared in Rock & Gem magazine. Click here to subscribe. Story by Deb Brandt.

The post Growing Up in a Rock Store first appeared on Rock & Gem Magazine.

Whether teaming together for all-female outings, or introducing the world of rocks and minerals to the next generation, women bring a new perspective, and sometimes a different approach, to this age-old endeavor.

Following Her Calling

For some rockhounding women, their affinity for interesting finds started at an early age.

“Ever since I’ve been little, I spent time at Crystal Park, (a recreational area in southwestern Montana where natural crystals abound),” said Brianne Scott, founder of the informal group, Rockhounding Women Montana.

Even though rocks were in her DNA from an early age, Scott went another route, instead earning a degree in Elementary Education, but it wasn’t the right fit. “It’s tough to be in the classroom all day long,” she said. So she stepped away from the profession and started collecting more rocks, mostly for the fun of it.

During her excursions around her Butte home, she said, “ There’s one piece that I have that’s a really neat little piece.” She said she spotted it caked in dirt, but discovered it was a combination of feldspar, smoky quartz castle-like structures, and albite, all coated with epidote. “It’s my favorite because of the complexity of it. It’s so unique.”

“I found myself with an overabundance of rocks,” she said, “ That’s how I got introduced to the rockhounding groups in Montana.”

Finding Other Rockhounding Women

Scott also discovered other groups on social media. Being able to trade or buy specimens not found in her area is one benefit of these connections, along with the opportunity to learn from others’ experiences.

“The biggest thing I’ve noticed about rock people is they are so friendly. I really get that sense of community,” Scott noted. “That’s where the lady rockhounding group started. I’ve gone digging with a lot of boys, but wanted to find more women.”

“We did one field trip in the summer. A group of us gals went to Crystal Park and went digging for the day,” she said. Scott is already lining up field trips, as well as learning opportunities for any of the women who want to participate. “It’s knowing what to look for on your hikes.”

Scott loves hanging out with any rock enthusiast, but women’s groups are sometimes less intimidating to new rockhounds. “I noticed a lot of the men are very technical with things,” Scott explained, which isn’t always conducive to a newbie. She believes women have a broader view of the landscape and notice what’s going on around, or in, the ground.

“Really it’s still a good partnership with men and women. It’s just a different dynamic,” she said.

When it comes to women, or really anyone, who wants to step into this fascinating world, Scott’s best advice is, “Reach out to folks. You’ll be able to find someone who is more than willing.”

Teaching the New Generation

While some rockhounding women are born with rocks in their pockets, others grow into it. Becky Weldy, a high school science teacher in Covington, Ohio, said her interest began during her post-graduate work. At that time, Wright State University offered a Master’s Degree program to educate teachers in geology.

“The professor opened my eyes to it,” Weldy said, particularly because the courses were far from mere academic musing with field trips in the Ozarks, Finger Lakes of New York, as well as the east coast of New Jersey.

Now she offers college-level courses in a high school class, enlightening the students to see beyond the textbooks. “I think a lot of the kids don’t seem to travel as much,” noted Weldy who aims to inspire them and bring the outdoors inside through her curriculum.

Field Trips & School

Weldy plans several field trips throughout the academic year, including visiting the Ohio Caverns, which are geological wonders in and of themselves, as well as Caesars Creek State Park in Waynesville. She said the area was developed by the Army Corps of Engineers in 1938 as flood control. The dam formed Caesar Creek Lake, which at 115 feet deep is the deepest in Ohio, and the spillway is rich in fossils such as trilobites and horn corals. This whole area is known throughout the world as a hotspot for geologists. A permit is required, but she turns the day into a multi-course study for her students.

Weldy also strives to bring her geology studies to the school. ”My other big project is behind our football field in eight acres of woods,” she said. Several years ago, teachers began working to turn the area into a working land lab cutting through new trails, spraying out the invasive honeysuckle, and replanting native trees.

Of course, the elementary kids already love exploring the space, plus Weldy incorporates the natural area into her geology classes with her 11th and 12th graders where they’re able to conduct real-world tests.

“It brings it into perspective to see and to touch,” she said. ”It is eye-opening to a lot of them.”

She hopes that even though she didn’t experience the wonders of geology until later in life, her students will have a jump on an appreciation of the rocks and minerals.

Rocks in Her Pockets

Dr. Kerry Griffis-Kyle, Ph.D., is an associate professor teaching classes involving complex ecosystems at Texas Tech University. Throughout her career, Griffis-Kyle primarily focuses on living things, but rocks are what make her happy.

She laughed when remembering her move from Syracuse to the Southwest when the movers picked up a particularly heavy box and wondered what could be in it. It read: “Rocks and Dead Things.”

Griffis-Kyle said, “That’s what it was because I am a biologist!”

The landscape at her home in Lubbock, Texas, is extraordinarily flat so for years she brought home larger specimens to add visual interest. Now that she is delving into the art of rock tumbling, she has shifted her focus.

“With the rock tumbling I’m picking up smaller rocks,” Griffis-Kyle noted. This focus on tumbling also requires a different form of attention. She’s learned to use a flashlight and black light to inspect the stones for structures within them. But she added, “I need to be better at identifying them. Some rocks are toxic. Some have mercury or uranium in them.” She pointed out that rocks with bright yellows and greens are particularly important to identify and handle properly.

Social Media Connections

In this new endeavor, she said that social media connections, especially with rockhounding women, are invaluable, whether it’s choosing the best rocks or specifics on using the tumbler. It’s a combination of art and science where a strong streak of experience goes a long way.

“I’m paying attention more to where the resources are,” Griffis-Kyle noted. When choosing where to camp, rockhounding is at the top of the activity list, and she enjoys visiting New Mexico. She said the state does an excellent job explaining where you can find different rocks and where it’s permissible to keep them.

She pointed out, “State by state you have to pay attention to what is allowed. Most of the time it’s okay to pick up a few rocks for personal use on federal land, but you can’t pick up fossils and artifacts. And never pick up anything on Park Service or DOD (Department of Defense) land.”

Always a scientist at heart, Griffis-Kyle appreciates the geological processes it requires to create colorful and unique specimens, but in the end, she said she looks for rocks because they make her happy. ”It’s kind of like art appreciation. Different things speak to different people.”

Gaining Knowledge in Groups

Although Valerie Steichen brought home rocks throughout her life, it wasn’t until she attended a rock and gem show in Missoula, Montana, that she noticed the long list of field trips hosted by the Hellgate Mineral Society. She was immediately on board.

“ They’re looking for young members,” said Steichen, noting the reality is many people within the group are over 70 years old, a common trend of these types of groups. There are lifetimes of knowledge waiting to be shared with the next generations, which is one of the main reasons Steichen appreciates the group.

“The main reason I go is so I get to walk in the forest with a geologist and learn,” she said. And besides the fieldwork, the club offers numerous educational workshops to keep everyone sharp.

Joining the Men

Whether it’s potentially the older membership and generational differences or an intimidation factor for women who are new to rockhounding, Steichen noted that when they go on field trips, the group is roughly 90 percent men.

But she is quick to allay concerns and encourages rockhounding women, and younger people in general, to join a local mineral or gem hunting group. “All of them are friendly,” she said.

Besides the innate knowledge of the landscape and the minerals found within it, Steichen noted, “What really struck me is their responsibility for nature.” She appreciates the knowledge of how to ethically dig for minerals, which is a growing concern in some regions when, at times, visitors take too much or do not practice Leave No Trace principles. By digging with one of these well-educated groups, new enthusiasts learn how to protect the resources for everyone.

For Steichen, one of her favorite finds is agates, which is the state rock for Montana. “I think I can pick out agate at a mile away. They look like ugly rocks, but they have billions of years of a story to tell,” she said.

And while the finds are beautiful, there are stories behind each one. Steichen said, “I remember where I found the rocks. There are memories to it and it means something.” So whether she is rock hunting with the Mineral Society members or looking for agates with her family, Steichen is the mineral matriarch who passes on this knowledge to anyone who wants to learn.

This story about rockhounding women previously appeared in Rock & Gem magazine. Click here to subscribe. Story by Amy Grisak.

The post Rockhounding Women first appeared on Rock & Gem Magazine.

“It is amazing that this small (25 miles long by 10 miles wide) batholith of the Spruce Pine Mining District lying in Mitchell, Avery and Yancey Counties is a world-class mineral deposit, and so important an ingredient to making the products we use daily,” says Alex Glover, whose 45-year career in the mining industry reflects a rock-solid list of geological credentials. “We often take for granted the role minerals play in the quality of life we enjoy today.”

Modern-Day Minerals

The U.S. Geological Survey describes a batholith as a type of igneous rock that forms when magma rises into the earth’s crust but does not erupt onto the surface. But the Spruce Pine, NC, Mining District isn’t just any old mass of cooled magma. The 380-million-year-old feldspar, mica and quartz deposits found in these three neighboring counties run most of our modern-day conveniences.

“Almost everyone uses products every day derived from the Spruce Pine Mining District,” Alex says. “Even more amazing is how it took colliding continents and millions of years to place this valuable resource in western North Carolina.”

“If you came to Mitchell County you wouldn’t have a clue as to the importance of this area to the entire world,” says Mandi Polly, who worked in quartz operations for 21 years before her role as executive director with the Mitchell County Chamber of Commerce.

“Think what would happen if the world couldn’t produce computer chips! This district supplies the production of fiber optic cable, solar components and many products in our daily lives. I honestly don’t think,” she grins, “that the majority of people in this area even realize the significance of our mines!”

Mineral City From the Ground Up

“Spruce Pine, NC, has mining deep in its roots and is known as The Mineral City,” she says. In addition to historic old mines like the Hoot Owl, the region has gem mines and the Mineral Museum of North Carolina. It is host to the NC Mineral and Gem Festival (now in its 64th year) and the 36th annual Grassy Creek Mineral and Gem Show.

A neat local side note she adds is how Spruce Pine Quartz supplies the sand for the Masters Golf Tournament, “because it’s so white and pristine.”

Early Mining Fame

Some of the oldest original mines — the Clarissa, Ray and Sinkhole — are believed to have been resourced hundreds of years earlier by First Nations in search of decorative mica for ceremonial events and, after Massachusetts Bay Colony recognized wampum as currency in 1650, for monetary exchange.

Alex says local lore recounts how word of North American mica mining by Native Peoples drew Hernando DeSoto to Spruce Pine in the 1540s, in search of mineral wealth he presumed would be gold and silver. But the only “silver” DeSoto found was Muscovite mica.

Wedgewood & Spruce Pine, NC

Two centuries later and an ocean away, English ceramics maker Josiah Wedgewood heard about feldspar and kaolin being mined by the Cherokee, from pegmatite deposits in what would become Macon County. The softer (Mohs 6) feldspar, in opaque shades of white to gray to rose, easily broke along flat faces (in a process known as cleavage) in comparison to irregular, curved breaks created by the conchoidal fractures of harder (Mohs 7) quartz.

Wedgewood had five tons of this “Indian clay” shipped to Staffordshire to use in the creamcolored earthenware that so entranced King George III’s wife, Queen Charlotte, that Wedgewood was granted permission to style himself, “Potter to Her Majesty” and call his fine pieces, Queen’s Ware. The feldspar clay had come from what would be incorporated in 1855 as Franklin, North Carolina. It was dubbed the Gem Capital of the World after discoveries like the 64.83-carat Carolina Emperor, the largest emerald ever found (2010) in North America.

Rubies & Sapphires

Baltimore gem prospector William E. Dibbell was a century ahead of his good instincts when it came to the rubies and sapphires the region would one day prove to yield but, at the turn of the 20th century, he did see untapped potential in the residual feldspar being discarded by mica mines like Flat Rock.

So did the Golding Sons ceramic plant in East Liverpool (Ohio), who liked Dibbell’s ceramic-grade feldspar so much that they wanted more, leading to the creation of the Carolina Minerals Company of Penland and the opening of the Deer Park Mine to satisfy the appetites of ceramic plants in Trenton, Wilmington and Liverpool.

The 1940s were a game-changer. Until then most of the work, especially the ore separation of minerals (feldspar, mica, quartz) was done by hand or crude machinery. Between 1944 and 1949, a chemical separation process jointly developed by feldspar mining companies, the Tennessee Valley Authority and North Carolina State University Minerals Research Laboratory, led to a high-capacity process still used today known as ‘Froth Flotation,’ that separates feldspar and quartz as well as mica and iron (mostly garnet) from rock and ore.

Not-So-Hidden Gems – Feldspar

“Modern-day mining methods, research, plant production, safety, and product development have enabled the extraction and use of these high-purity mineral resources from the earth to enhance our quality of life,” says Alex.

It’s that extraordinary purity that makes the natural treasures from Spruce Pine, NC, so valuable.

Feldspar makes up roughly 65% of the igneous pegmatite in Spruce Pine, NC, and is an important source of aluminum, potassium, and sodium for making glass – from windshields and computer screens to baby bottles and light bulbs.

“Feldspar is the most abundant mineral on the earth’s surface and crust, but its purity as an ore is rare,” he says.

Spruce Pine, NC, feldspar has come a long way from Wedgewood ceramic teacups. Today, feldspar serves as a flux to fuse or melt other ceramic ingredients at a lower temperature, cementing the crystalline phases of other ingredients together while imparting improved strength and durability. “Its special qualities allow ceramic manufacture of pottery, plumbing fixtures, electrical insulators, tile, dinnerware, planters, and structural ceramics to name a few.”

Mica in Spruce Pine, NC

If feldspar composes 65% of the local pegmatite, mica accounts for another 10% of deposits. Originally used in heat-resistant glass for wood and coal stoves (isinglass), and insulating World War I and II radio tubes, the same properties are used today as a reinforcing plastics and oil well drilling fluid additive, in specialty component electrical insulation, metallic flake automobile paint and cosmetics.

The flat particle shape of the silver-to-white variety called muscovite mica lends itself to drywall joint compound and sheetrock joint cement.

“Muscovite’s flat particle shape and light color allow it to serve as an anti-shrinking agent,” Alex explains. “It applies as a smooth, damp putty, but because of mica’s flat particle shape, it interlocks the mud as it dries, thus reinforcing a filled area without shrinkage and also serving as a fire retardant within drywall joints.”

In the early years of production, the quartz composing 25% of this pegmatite was treated as discarded waste but now it is the most valuable component of the region’s three major minerals. “Froth Flotation enabled better separation of the three minerals, especially the quartz,” he says, thus ensuring that Spruce Pine Quartz ranks among the most important strategic minerals in the world today. Its lower-purity quartz is used as industrial white sand and valued for use on such fine golf courses as Augusta National Course in Georgia, host of the Masters Tournament. More recently, it has been incorporated into the development of quartz countertops for the home.

Down to the Roots

“It’s important to know that even before computers were a concept, mining was a very important part of Mitchell County’s economy and history,” says Mandi. “The quartz business helped my family as I was growing up. My husband’s work in rocks and sand supports our family. My son-in-law works in the quartz business. So it is definitely supporting future generations!

“As of 2022, according to the NC Department of Commerce, mining corporations are the second-twelfth-largest employers in Mitchell County. The mining companies are not only crucial for supplying many jobs but are also very active in the communities. Many serve on boards, help with local schools, sponsor sports teams and host events, support nonprofits, and give back, through volunteer hours and countless other projects.

“This is where I choose to stay and raise my children and grandchildren. We truly are – all pun intended — a hidden gem. Spruce Pine, NC, hasn’t been called The Mineral City by chance. Because that is who we are, down to our roots.”

This story about the Spruce Pine, NC, mining district previously appeared in Rock & Gem magazine. Click here to subscribe. Story by L.A. Sokolowski.

The post The Spruce Pine, NC Mining District first appeared on Rock & Gem Magazine.

Identifying the Risks of Radioactive Minerals

Understanding which parts of your collection may pose a risk is the first step. You might have just a few individual, radioactive mineral specimens. But some large rocks may also contain an amalgamation of multiple types of potentially radioactive minerals. In addition to these radioactive minerals, there are also daughter products that are created as the result of radioactive decay. Daughter products, such as radium, radon gas and uranium, are themselves radioactive.

According to Alysson Rowan, author of Here Be Dragons or The Care and Feeding of Radioactive Mineral Species, some radioactive minerals may even be hiding in plain sight. “A specimen that doesn’t look very good because it’s not well crystalized — somebody may cut that into a decorative stone and mount it for wearing,” Rowan says. “You can find these things on sale, and there’s no mention of the fact that it is radioactive.”

Based in Holsworthy, England, Rowan is also a former radiation safety worker with extensive training in geology. She continues, “There’s no mention that this is not something that you would want to wear, so, people buy these things and wear them in ignorance.”

Detection Equipment

Because uranium minerals tend to be very colorful, they’re among the most popular with collectors. “The other thing is that there are a lot of them that are fluorescent,” Rowan says. “With uranium minerals, you tend to get greens and yellows, but there are minerals that glow blue, and red, and I think there’s even one that’s now known to fluoresce purple.”

Incidentally, to test the radioactivity of your stash, you’ll want to purchase a handheld radiation detector. “If they’re going somewhere to collect uranium minerals or they expect to find uranium minerals, a handheld ‘Geiger counter’ is a must-have,” Rowan suggests. “Of course, they’re not all Geiger counters now. . . . A lot of them are scintillators which are a lot more sensitive and a lot more durable. They generally show how much radiation they’re detecting either on a meter or on an alphanumeric display.”

You can also find used Geiger counters for sale online. “A lot of people buy them second-hand on eBay,” she says. “The American Civil Defense monitors are very, very popular because there’s a lot of them about.”

Saléeite and autunite are two colorful — and radioactive — minerals. “In bright sunlight, you can see the fluorescence,” Rowan notes. Both are in the bright yellow-green range.

Just don’t get too attached to that autunite, as it will literally disintegrate. “Autunite is what’s known as a metamict,” Rowan explains. “It decays radioactively, and the radiation damages the crystal. Inside a few years, it’s just a pile of dust. . . . And, so, autunite will actually spread all over the place.”

Radiation Effects

Containing that radioactive spread is paramount because the negative effects of radiation on the body are cumulative. In other words? The radiation you absorb builds up over time. You can inadvertently expose yourself to radiation internally by absorbing contaminants through your skin. You can also inhale or ingest radioactive contaminants.

The acute effects of radiation exposure can range from erythema — akin to a deep tissue sunburn — to renal failure. “The uranyl minerals—that is uranium oxide as a radical—are toxic to your kidneys,” Rowan says. “So, that is what you’ve got when you pick up most fluorescent minerals. It’s uranyl phosphates, uranyl nitrates—they are highly toxic.”

Over the long term, exposure to some radioactive compounds can even result in bone cancer and leukemia. In her book, Rowan writes, “Inhaled uranous and thorium compounds, and to a lesser extent the uranyl compounds will result in both toxic and radiation damage to the lung. Long-term effects will include bronchitic and emphysema-like symptoms as well as a range of pulmonary and pleural cancers.”

Smoke Alarm

Keeping cigarettes, incense, and other smoky stuff away from radioactive specimens is especially important.

For safety’s sake, you should never eat or drink while handling radioactive minerals. Applying a quick smidge of lip balm’s another no-no. And smoking is right out, too.

“The thing about smoking is one thing that you do is that you handle the rock and you put your cigarette to your mouth and you’ve immediately got rock dust on your lips,” says Alysson Rowan, the author of Here Be Dragons or The Care and Feeding of Radioactive Mineral Species.

What’s more, let’s say some of your specimens contain uranium. As uranium goes through its multiple stages of decay, it eventually releases radioactive radon daughter products and radon gas. “The airborne activity from radon daughters and radon gas itself will attach themselves to smoke,” Rowan continues. “So, when you re-inhale smoke, you’re inhaling the radioactive contaminants in the atmosphere.”

In her work, Rowan writes, “It has been noted that the presence of blue smoke from cigarettes (the plume that rises from the burning tobacco) collects the radioactive radon daughter products more surely than any other means of concentration. This means that the spent smoke you breathe in a high radon concentration area is bringing those radioactive materials into your lungs in a form which tends to remain inside your body.” Such radiation exposure in the human body is cumulative. Rather than dissipate, the radiation exposure adds up. “The consensus of scientific opinion is that a given dose from radon is possibly 10 or 15 times as dangerous to a smoker as to a nonsmoker,” Rowan notes. To mitigate this risk, never smoke in areas where you keep radioactive specimens.

Minimizing Exposure

Although different minerals pose differing degrees of risk, if you are pregnant, you should avoid contact with radioactive minerals altogether. As for young children? “Before puberty, we are a lot more susceptible to radiation damage because of the rapid cell division,” Rowan says. “Children should not be around. . . radioactive minerals more than absolutely necessary for their study.”

There are several precautions you can take to minimize your overall radiation exposure and still appreciate the radioactive specimens in your collection. Besides the degree to which a mineral is radioactive, the amount of the mineral in question matters as well as the cumulative amount of time that you spend in direct contact with it.

“If you sit with a pound of uraninite using it as a paperweight on your desk, that is going to give you a problem eventually,” Rowan maintains. “If, on the other hand, you have that pound of uraninite and it’s in a lead-acrylic case, that reduces the dose rate and, therefore, it’s not quite the same problem.”

Display Do’s and Don’ts

“You also have to take into account how far you are from that specimen,” Rowan adds.

When you increase the distance between yourself and the specimen, you decrease your potential radiation dose. Adding shielding materials like lead, wood or glass can further reduce your radiation exposure.

“For the most part, you put [your collection] on display in a cabinet,” she says. “The idea is that you’re keeping dust off of your specimens, but you’re keeping dust from the specimens fixed.”

Regarding those uranium-rich minerals, keep in mind that uranium decays into radium which, in turn, will decay into radon gas. Because this heavy, radioactive gas can easily migrate, you should air out your uranium mineral display cases periodically. “I’ve done this with my own cabinet,” Rowan says. “You open the cabinet and stick your [radiation] meter in and the radiation count goes up. And, over about half an hour, the count rate goes right down, because the radon daughters in there only have a short half-life.”

Still, she cautions, “If you’re a serious uranium collector, then it’s probably a good idea to have vented cabinets—venting to the outside world.”

Also, never store or display uranium minerals in a basement. “Radon gas is an awful lot denser than air,” Rowan explains. “It’s a big atom and it will hang around for a couple of weeks.”

Handling How-To’s

If you do need to handle a radioactive mineral specimen, don’t dally. “If you’re working with it for too long, that’s all additional exposure,” Rowan says. “So, the amount of time that you’re in contact with the rock, you need to minimize it. And you need to make sure that you don’t spread contamination everywhere.”

To that end, she suggests wearing protective clothing and disposable gloves and protecting your work surface with a disposable covering. Washing carefully with soap and water is also key. “If you handle a radioactive rock, you’ve got radioactive rock dust on your fingers and you’ve got to wash it off,” Rowan says.

Finally, to prevent ingestion or inhalation of radioactive contaminants, never eat, drink or smoke when working with radioactive minerals, and, Rowan concludes, “Don’t be paranoid, but do take care.”

This story about radioactive minerals appeared in Rock & Gem magazine. Click here to subscribe. Story by Susan M. Brackney.

The post What are Radioactive Minerals? first appeared on Rock & Gem Magazine.

The Stone Age

The Stone Age lasted until the end of the Neolithic era when we learned to start using metals and transitioned into the Bronze Age. The Stone Age is three distinct periods recognized by researchers, known as the Paleolithic, Mesolithic and Neolithic eras. The suffix lithic means “stone.”

Most of the Stone Age occurred within the Ice Age. Early humans hunted the Megafauna of this period such as saber-toothed cats, mammoths, mastodons, giant sloths, giant bison and relatives of the modern deer. Weapons were needed to kill these animals for food, to take their hides for clothes, warmth and protective structures, and to use their bones for numerous purposes.

The Stone Age Eras

The longest of the Stone Age eras was the first. The Paleolithic era lasted just shy of 2.5 million years, ending between 11700 and 9600 BCE. The stone tools and weapons from this era are known as Oldowan and Acheulean. Several cave paintings date back to this era and depict scenes of stone weapons. The end of this period coincides with the end of the ice age.

Middle Stone Age

Dates for the Middle Stone Age, or the Mesolithic era, are harder to pin down. This period represented an advancement in weapon and tool-making skills and is greatly regional since there was not a whole lot of exchanging of ideas and technologies. In some parts of the world, it began as late as 8,000 BCE. Regardless of the exact dates, it was the shortest of the three eras. It is notable though for many advancements in weapon and tool-making skills. Weapons associated with this era were chisel-pointed burins (akin to awls), blades and backed knives, scrapers, cutting tools known as tranchet adzes and multi-purpose tools.

Neolithic Era

The Neolithic era, also the last era, began as early as 8,000 BCE in some parts of the world and ended between 3,000 and 2,700 BCE. This was the last period where humans relied exclusively on stone, bone, antler, or wood weapons and started experimenting with metals. Stonehenge dates back to this period. Agriculture became more prominent during this time and a lot of stone weapons and tools were used for digging and farming. This period saw the rise or continued improvements to adzes, arrows, axes, blades, chisels, and other dual-purpose tools used for digging and striking.

Axes and Knife-like Weapons

Axes were broadly used throughout much of the Stone Age. Axes were useful in close combat, good for clearing a path while in pursuit of their target, but even more so when preparing a kill to be eaten. As the millennia progressed, so too did the shape and sharpness of the stone axes our forebears made. By about 320,000 years ago, axes had evolved from larger, fist-sized axes, to smaller and more sophisticated blades and points. A specific type of ax was developed, known as a “chopper.” This was used for more detailed work such as dividing up meat or cutting into skin and fur.

Blades and scrapers were crafted from smaller, sharper stones than those used typically for axes. There was no uniformity in their overall size or weight. A tribe, clan or family might have several different sizes to be used as each circumstance dictated. When made of obsidian, these blades were especially sharp. As time went forward, and agriculture developed, these would be affixed to longer sticks and become the world’s first scythes.

Projectile Points

Projectile points were used for arrows, spears and harpoons. The traditional arrowhead is among this group. Projectile points were the premium weapons for hunting. Early humans located near water utilized this technology to make harpoons for hunting fish and larger marine life. Evidence suggests that early mankind was adept enough at using harpoons, they could spear larger fish, including swordfish and whales. Rope was attached to the harpoon shaft so the kill could be pulled to shore.

As soon as early humans learned how to create composite tools, they affixed sharpened, triangularly pointed stones onto the end of a wooden shaft and adhered them with sinew or plant fibers. As the handle part of these composite tools has long since decomposed, it can be difficult to know whether a projectile was affixed to an arrow or a spear, so researchers do not make that distinction.

Around 300,000 years ago, humans began to adhere projectile points to sticks via a method known as hafting. This allowed the pointed stone and stick to be a singular weapon, much less cumbersome than previous methods. Skilled weapons makers would use fire and heat to perfect this attachment. Initially, these would have been used for jabbing, until the advent of the Atlatl — a device that evolved into the bow. It acted as an extension of the arm and allowed projectiles to be hurled much farther and faster with more accuracy.

Slingstones

An overlooked category of stone weapons is the sling stone. This is probably because not all sling stones were honed to a particular size or shape. They were potentially used in the form they were found. These first appeared late in the Stone Age. Piles of sculpted, similarly-sized, oval or oblong rocks with pointed ends have been found in parts of the Middle East.

When used in their found form, these are the most rudimentary of weapons. When formed with pointed ends into roughly uniform size, and intended to be flung with some kind of a sling, this evidences great thought and advancement. This allowed for greater accuracy because a formal size could be used for practice. Besides their obvious use in combat or hunting, these sling stones are also thought to have been used to aid herders when controlling predators and steering a flock. Scientists assume this because sling stones are often found in areas where flocks were located.

Multi-Functional Tools & Weapons

As the Stone Age came to a close, early humans became adept at making multi-use weaponry. This makes sense as it reduced the number of things to carry and is evidence of the evolution of stone weapon making. A single stone weapon/tool from the Mesolithic could simultaneously have one side that was used as a knife, one side as a hammer or striking surface, and one side as a scraper. As farming arose, the need to dig into the soil and clear land became important as well.

It was not uncommon for some skilled tool and weapon makers to have actual tool kits of stones to do a variety of tasks. Regional differences have been found suggesting these skills were passed down and that communities had distinct identities or cultures.

This story about the ancient artifacts previously appeared in Rock & Gem magazine. Click here to subscribe. Story by Chris Bond.

The post Ancient Artifacts: Rocks as Weapons first appeared on Rock & Gem Magazine.