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.

Purchasing Ghost Fire Agate

Since this is a new material, it’s not readily available everywhere just yet, it can be found mostly on Facebook in some of the rock sales forums. When buying ghost fire agate, it’s best to buy from pictures that show at least one side faced, or cut in half, so that you can see what you are getting inside. This material has a great deal of matrix on the outside, and a greater portion inside. It’s best to see how much agate is there before committing to a price that might not yield enough usable agate area to cab since it’s purchased by the pound.

Slabbing Ghost Fire Agate

When starting to slab this material, I cut from two sides, north and west. This way I could see if there were drusy pockets or completely agate-filled nodules. I was able to choose which patterns I liked best. There is no definitive direction to load the stone in the vice, as there are no north-to-south types of patterns in this stone. Start off with the flat sides held tight in the vice. Once you get it cut, if there are large areas of the matrix in the center, I like to cut through them, and downsize the larger stones, so that I can cut smaller ones on a 10-inch trim saw. That way it’s much easier to switch directions with each slab cut, instead of continually loading a vice on the larger saws.

Once your slabs are cut, and it’s time to draw preform designs, you can include some of the matrix that’s still solid enough to cab and not worry about undercutting too much. I have noticed that the plumes grow from areas of the matrix, so I designed them in a way that the matrix is used as a partial framing of the cab. Other times, you can run into patches of beautiful purple and blue agate and isolate that as your cab. The other pitfall to look out for is the calcite that seems to border some of these areas. It’s much softer than the agate and will undercut fairly easily, especially if it’s on the edge of your cab.

Cabbing & Finishing

The cabbing process is fairly routine to most agates, but there are still several ways you can go to obtain the same results. Most lapidaries use a 6-diamond grit wheel setup. For those who still have, or use silicon carbide belts on a poly arbor, they seem to work well in the beginning stages as long as they are on two separate machines, and you rinse the cab off before going back to diamond grit, to keep from contaminating the machine with diamond wheels.

Start shaping and doming on the 80-grit steel diamond wheel. Once you have that portion done, you can continue to a 140 soft resin diamond wheel, or switch to a poly arbor set up, with 100 and 220 silicon carbide belts. The 100 will quickly smooth out the cab and remove all the deep scratches from the 80-grit. The 220 will completely remove any remaining scratches, making it quick and easy to finish the rest of the way on the diamond wheels, starting back on the 600, and all the way up to the 14k.

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

The post Ghost Fire Agate: What to Cut first appeared on Rock & Gem Magazine.

1. What is Carnelian?

Carnelian is a cryptocrystalline variety of quartz known as chalcedony, or agate. It ranges in color from yellow to orange to red and reddish-brown. Most prized are warm oranges and vivid reds. It forms as low-temperature deposits that fill seams, cracks or cavities and is often found as nodules. At Mohs hardness 6.5 to 7, with nice translucency and luster, it’s a fine lapidary stone.

2. Why is Carnelian Red?

The reddish-brown color of an old nail comes from iron rusting or oxidizing. Similarly, chalcedony is colored red if infiltrated by solutions bearing iron oxides during formation.

A caution! You may think you’ve found a beautiful red carnelian, but often a red exterior is only skin deep. When cut, the interior may be yellow. This reflects different concentrations of iron oxides that were in the solution as the nodule formed.

3. How Was Carnelian Named?

Per one source, “carnelian” comes from the Latin word carnis, or “flesh” because of its red color. Another source claims it comes from the Latin word cornum, referring to the glossy red cornelian cherry.

4. Is it Carnelian? Or is it Sard?

In ancient times, carnelian was referred to as sard. It is a gemstone mentioned in the Bible. The Roman naturalist Pliny the Elder said this referred to the Lydian city of Sardis in present-day Turkey. Others say it came from the Persian word sered meaning “yellowish-red.” Then there’s the Greek word sarx, meaning “flesh.”

Sard is russet-colored, or deep dark brown with a reddish-orange tinge. Remove the brown and you have carnelian. The difference between carnelian and sard is a matter of degrees, and the two names are sometimes used interchangeably. The amount of iron oxide influences the color range.

5. How Does Sardonyx Differ from Sard & Carnelian?

Forget carnelian versus sard. We also have sardonyx. This is a striped version of carnelian or sard with bands of white chalcedony alternating with red/brown stripes. Onyx is a Greek word meaning “nail or claw,” and sardonyx was said to resemble a fingernail with a white tip above a pink base. The stone has long been valued for the color contrast between layers.

6. I Bought a Red Stone. Is it Carnelian?

Dull light-colored chalcedony can be stained and dyed with iron salts. One source claims many stones sold on the market as carnelian are actually artificially stained chalcedony. Buyer beware!

7. Where Can I Find Carnelian?

It’s said the finest carnelian is from India, and the face of the Taj Mahal bears red flowers crafted from inlaid carnelian. But carnelian has been sourced from many nations including Brazil, Mexico, Saudi Arabia, Sri Lanka, Thailand, Australia and Germany. Material from Madagascar is currently prominent on the market. In the U.S., Oregon is notable, with nodules found on coastal beaches and in river gravels.

8. Did the Ancients Use Carnelian?

Because of its lush colors and ease in crafting, carnelian has been used in jewelry since at least the 4th millennium B.C. Carnelian beads have been found in Bulgarian grave sites from the Early Neolithic 8,000 years ago. In 2000 B.C., Egyptians used it for beads and cabochons, often set in gold alongside lapis. Ancient Greeks and Romans used it for intaglios (engraved stones) and set in gold as signet rings for sealing letters with wax.

9. What Lore & Legend Surrounds Carnelian?

The traditional birthstone for July is ruby, but one alternative stone is carnelian. The Zodiac birthstone for Virgo is peridot, but also carnelian. And carnelian shows up in Judeo-Christian religious traditions. For instance, high priests wore a gold filigree breastplate adorned with 12 stones, including sard, to represent the 12 tribes of Israel.

Because they were the color of blood, in ancient and medieval times red stones were considered talismans associated with life and were believed to attract the attention of good spirits while warding off evil. Carnelian was believed to calm tempers and to “still the blood” from rage. On the other hand, while stilling the blood, carnelian was also believed to promote courage in battle and to stir eloquence within shy speakers. Today’s New Age practitioners of healing stones say it purifies the blood, provides strength and soothes emotions.

10. Is Carnelian Still Used Today?

Just like the ancients, lapidary artists today value carnelian, whether slabbed and domed as cabs to set into earrings and pendants or to craft beads. It’s also carved and incorporated into intarsia. Colorfully translucent, hard and durable, and taking a glossy polish, carnelian has stood the test of time.

Rough or tumble-polished pieces make great display specimens.

This story about carnelian previously appeared in Rock & Gem magazine. Click here to subscribe. Story and photos by Jim Brace-Thompson.

The post Carnelian: Top 10 Facts first appeared on Rock & Gem Magazine.

Chalcedony

The general term, chalcedony, refers to varieties of quartz where microcrystalline and cryptocrystalline crystals intertwine and grow together. There are many varieties of chalcedony in different colors and patterns. They are plentiful and popular. Gem-grade chalcedony is generally light blue, white or gray and often called holly blue. Chalcedony’s name is said to come from the Greek port of Chalcedon.

Varieties of Microcrystalline Quartz

Agate – Curved banded variety

Jasper – Opaque, red or green varieties

Chert – General name used for compact, hard rocks that contain microcrystalline quartz

Flint – Afiner-grained, harder type of chert, Ohio’s official gemstone

Carnelian – Orange-red opaque mineral

Onyx – Parallel banded variety

Sardonyx – Red sard and white chalcedony

Chrysoprase – Translucent, apple-green color

Bloodstone – Dark green with red spots of iron oxide

Petrified Wood – Over time chalcedony replaces wood while preserving the growth rings

Happy Micro Quartz

Microcrystalline quartz has so many beautiful varieties that it’s often interwoven into our pop culture. It’s a happy birthday for these micro quartz birthstones – bloodstone (May) and sardonyx (August). Chalcedony itself is said to bring stability and balance to its bearer.

This story about micro quartz minerals previously appeared in Rock & Gem magazine. Click here to subscribe. Story by Richard Gross and Pam Freeman.

The post Micro Quartz Mineral Basics first appeared on Rock & Gem Magazine.

Beyond the formal definitions, agates are fun! They are common and abundant and can be collected almost anywhere. No matter where you live, there is probably an agate field within easy reach for a day trip.

Their abundance makes most agates inexpensive at rock shops and gem shows. Plus, they can be enjoyed “as is” or cut, crafted, and tumble-polished into lapidary wonders.

What are agates? The perfect stones for the beginning collector!

How are Agates Formed?

The best thing about agates is the variety they show in colors and patterns. An agate may grow as an undifferentiated mass. It may be all one color, or it may have inclusions or colorful concentric bands.

Agates precipitate out of solution and grow in seams within other rocks or within vesicles in basalt or cavities within limestone, later eroding out as nodules.

What are Agates? List of Common Varieties

While there are many, consider a few of the more common varieties.

Fortification agates have concentric bands that look much like a “fort” circling a castle.

Waterline (or water level) agates have straight bands that were formed by gravity as layer after layer of agate was set down.

Eye agates have spots on the surface.

Flame and plume agates are very similar. Flame agates have swirling red lines that look like fire, whereas plume agates have interesting inclusions that look like ferns or plumes of smoke.

Sagenitic agates have inclusions, but these are needle-shaped.

Moss agates are similar to plume agates, but the plumes permeate the entire rock, often in shades of green, brown, yellow, or red.

In addition, there are shadow, tube, seam, polyhedral, enhydro, fire, iris, and many more varieties of agates. This wonderful variety makes agates a whole lot of fun to collect!

Look through the agates in your own collection. How many varieties can you spot?

This Rock & Gem Kids column about what are agates appeared in the August 2021 issue of Rock and Gem magazine. Click here to subscribe!

The post What are Agates? Explore Common Types first appeared on Rock & Gem Magazine.

Within the roots, he discovered a few thundereggs, which lead him to further explore that area. There he discovered what would become his newest claim.

Since 2009, Jason Hinkle has owned and operated the mine and enjoys the rewards of mining his claim each year.

Fallen Tree Thunderegg Qualities

Fallen tree thundereggs are unique, with an outer rhyolitic shell, with mushroom rhyolite patterns, filled with various types of chalcedony (including agate), blue opal, quartz, and other inclusions. You never know just what you will get when cutting one in half!

Fallen tree thundereggs might not have all the prestige as many other Oregon thundereggs, but rockhounds and lapidaries will appreciate all the gorgeous variety that comes from this mine.

How to Purchase

When purchasing thundereggs, you can always buy precut halves to be able to choose the top-notch quality rock that catches your attention. But, there’s something to be said about the rush you get from cutting your own, to reveal a treasure that’s millions of years old and waiting to be opened. With any thunderegg, you never know what you’ll get until you cut it open. There are many times the inside will be a dud, and you have to keep cutting several until you get some good ones. This is to be anticipated.

Most of the thundereggs from this mine are generally baseball to golf ball size. Some lapidaries like to use the geode grab holder in the saw, but with these, I like to just cut them by hand on a 10-inch trim saw. You usually get the best results from cutting top to bottom, but experimenting with these can be a lot of fun. You can also yield various nice patterns by crossing-cutting.

Cabbing Thundereggs

Cabbing thundereggs is relatively routine, however, there are a few pitfalls to watch. The first is the differing hardness of materials. The outer rhyolite is much softer than the chalcedony centers. The rhyolite can also detach from the center agate, so stabilization treatments might be necessary before trimming out your preforms for it to hold together. There also might be a few fractures in the center, but you can always just work around those areas.

To start your cabs, trim out your preforms, and grind your shapes on the 80-grit steel wheel. Be careful doming the top being cautious not to break off any rhyolitic edges. Once the preforms are shaped, move onto either the 140 grit soft resin wheel or 220 soft resin.

At this point, dry off the cab thoroughly to check for scratches, any deep scratches should be removed by now.

Any micro-scratches can be dealt with on the next wheel.

Finishing Up

With material like this, I like to have a separate setup off to the side with silicon carbide belts on self-expando wheels. The silicon carbide belt smoothly removes scratches and is far less aggressive. This gives it less of a chance of breaking off any rhyolite edges and less undercutting from the hardness differences. From this point on, it should be relatively routine and easy, finish through your sanding wheels and polishing wheels and you can end at either the 8k grit or 14k grit wheel for a super nice polish.

This story about fallen tree thundereggs appeared in Rock & Gem magazine. Click here to subscribe. Story by Russ Kaniuth.

The post What to Cut: Fallen Tree Thundereggs first appeared on Rock & Gem Magazine.

Agate Facts

Agate has a seven Mohs hardness, making it desirable in the lapidary trade. Agate is translucent and exhibits a vitreous luster. As with other varieties of quartz, its chemical formula is SiO2. The name agate comes from the river Achates in Sicily and was given that name by the Greek philosopher, Theophrastus. Agate names can be derived from the location where they are found such as Botswana agate or Laguna agate or because of a feature they exhibit like lace, fire or moss.

How Agates Are Formed

Agate formation takes place when silica solutions fill voids in cavities layer by layer such as in Florida’s agatized coral. The voids typically are in solidified volcanic lava flows and the layering over long periods of time can result in different colors because of chemical changes in the silica solutions. The layering can deposit the chalcedony in concentric circles around the wall of the cavity or build the layers up from the bottom of the cavity.

Decorative Agates

Agate is used to produce cabochons, beads, and free-form objects in jewelry making. Book-ends, ashtrays, and sculptures are also made using agate.

Positively Agate

In the metaphysical realm, agate is said to change negative energy into positive energy and to heal anxiety and internal anger. Agate may also help with concentration and boost mental function.

Where to Find Agates

In the United States, agates are found in Oregon, Wyoming, Montana, Arizona, Idaho, California, Washington, New Mexico, Iowa, Wisconsin, Michigan, Minnesota, Utah, Florida, Colorado, Arkansas, and Nevada. Around the world, they are found in Australia, Germany, Brazil, Czechia, Botswana, Mexico, Morocco, Afghanistan, Argentina, Canada, Chile, India, China, and over 40 other countries.

This agate field guide appeared in Rock & Gem magazine. Click here to subscribe. Story by Richard Gross.

The post A Field Guide to Agate first appeared on Rock & Gem Magazine.

How Agatized Coral Formed

Florida agatized corals are the skeletal remains of colonial animals, known as anthozoans, that died 25 to 38 million years ago. The actual skeletal structures are very easy to see in some specimens and can be used to identify the coral species.

The skeletons consist of limestone (CaCO3 ) and the coral becomes agatized when the coral voids are filled with silica-rich water and the limestone is replaced by chalcedony quartz (SiO2 ) and common opal.

Chalcedony that is translucent and colored is called agate.

The replacement process takes millions of years and results in what geologists refer to as a pseudomorph –a crystal consisting of one mineral, but having the form of another which it has replaced. Occasionally, very small clear visible quartz crystals will form after the chalcedony layer; but, it is the richly colorful agate layer that we find so attractive.

Is Agatized Coral a Geode?

As far as geodes go, these wonders of an ancient ocean are atypical. While some are the round shape we generally see in most geodes, many have shapes that vary.

Some have questioned whether these specimens should even be considered geodes, however, most geologists today, including June Zeitner and Brad Cross in Geodes: Nature’s Treasures, feel they do fit the criteria for being a geode.

How to Collect

I field-collected Tampa Bay coral in Hillsboro Bay in 1964 and as far as collecting goes it was not a pleasant experience!

I waded out into the bay barefoot and stirred up the mucky bottom with my feet. Occasionally, I would feel something solid and would reach down and bring it up out of the slimy mass on the bottom. Most times it was just an ordinary rock.

The few pieces of coral I found were all very small. I was quite disappointed until I returned home, cleaned the pieces up, and carefully cut them on my lapidary diamond saw. It was then that I realized the allure that these specimens hold for collectors.

There, in a specimen one and a quarter inches across, was an array of swirls of red, blue, black, orange and white that was just stunning!

Agatized Coral History

Archaeologists have found tools, knives, and weapon points fashioned from agatized coral dating back to 5,000 B.C. The more recent discoveries date back to the 1840s when the coral was found at Ballast Point in the Hillsboro Bay area. Hillsboro Bay is part of the Tampa Bay complex and hence the referral to coral found in this area as Tampa Bay coral.

Ballast Point has an interesting history related to the coral. Sailing ships carrying goods between the port of Tampa and Europe would use the coral as ballast to adjust the depth of their hulls.

During the early 1900s, there was an intense rivalry between young men living in Ballast Point and young men living in Port Tampa. The rivalry was over the affection of the Ballast Point young ladies. The Ballast

Point boys would collect a large supply of the most round “geode rocks” to use as ammunition to repel the Port Tampa boys.

The Port Tampa boys not having access to the geodes would throw large chunks of coal.

Most times geodes triumphed over coal!

Collecting Agatized Coral

For many years since its discovery, Tampa Bay coral was the best known and most widely field-collected of the Florida agatized corals. Collecting opportunities are now limited as most of the area has been developed. Construction areas provide some of the best places to collect, but be sure to ask permission first.

The other main areas where Florida agatized coral is found are in the Withlacoochee/Suwannee riverbeds along the Florida Georgia State line and the Econfina River area north of Perry, Florida. Currently, Withlacoochee River coral is the best field collecting choice.

Collecting is usually done by diving using a snorkel or aqualung and requires a boat.

Coral Colors

Tampa Bay geodes are notable for their wide array of colors that include black,yellow, honey brown, red and blue. The blue chalcedony is spectacular and may appear with swirls of yellow and red in the same geode.

The formation of drusy quartz is more common in Withlacoochee coral. Drusy quartz crystals are very tiny crystals that form on top of the chalcedony and give a sparkly appearance to the inner surface of the geode. The appearance of Withlacoochee coral is different from the Tampa Bay corals, but small fragments can be foolers.

References to Econfina River coral are not commonly found these days and I only have two specimens in my collection.

Econfina agatized corals are noteworthy as they frequently show distinct banding in the agate.

State Fame

In 1979, Florida agatized coral was designated by the Florida Legislature as the official state stone. Besides being displayed by individuals and museums in their collections, the coral has lapidary uses.

This story about agatized coral previously appeared in Rock & Gem magazine. Click here to subscribe! Story and photos by Richard Gross.

The post Florida’s Agatized Coral 101 first appeared on Rock & Gem Magazine.

Finding Hava Ridge Jasper

This material isn’t heavily available in the market as it’s a very new find but you can buy it directly from Nik on the Hava Ridge Jasper Facebook page. Each chunk of rough will vary in colors and patterns. If there are certain colors you are looking for, buying slabs might be the way to go. If you want a good assortment, I would suggest buying a few pieces of rough and experience slabbing this material yourself.

Starting to Slab

As you begin the slabbing process, this material usually doesn’t have much of a rind, so it’s best just to wash it off and pick which side you want to cut from first. As with some materials, there is a direction you want to cut to show the desired patterns, but with Hava Ridge, you can start at any angle and achieve nice results. With many of the rough pieces I have slabbed, after cutting the first end piece off, I usually choose to continue in that direction, or if it’s not the desired pattern, I will turn it and cut from another side.

Once all your slabs are cut and you are preparing your preforms, just note that Hava Ridge is a hard and very solid jasper, but it tends to have micro pits in it. These pits can be worked around, or even worked into your finished cabs, but if you want a flawless finish, you can stabilize or fill the surface area with epoxy before the cabbing process.

As with most porcelain jaspers, when shaping the preforms on the course 80 grit steel wheel, the back edge likes to chip on the edge. This will have to be addressed once you move on to the 280-grit stage and smooth the outer edge.

Cabbing Hava Ridge Jasper

Cabbing Hava Ridge is fairly easy, I shape and dome on the 80 grit steel wheel, and like to move on to the 60-soft resin wheel to quickly remove the deep scratches and flat spots. If you don’t use 60 grit, this can also be done with your 220-grit steel wheel, it will just take a bit longer. From there, you can go right to your 280 soft resin wheel to smooth everything out and make sure there are no scratches beyond this point.

Stopping periodically and drying it off will help find any remaining scratches.

Many times it can be hard to see them on darker materials and especially when they are wet. A trick you can use is to dry the cab off, find the scratches and mark them with a Sharpie pen. The ink will sink into the scratch, and as you continue to grind, you should grind the ink right off. It should be ready to move onto the 600-grit wheel to start the polishing stages.

To finish off your cab, work your way up from the 1200 to 14,000 grit wheels and this will yield a beautifully polished cab. If you’d like to take it a step further to gain more of a mirror polish, aluminum oxide on a leather buff, or Zam on a felt tip Dremel works wonders!

This story about Hava Ridge jasper appeared in Rock & Gem magazine. Click here to subscribe. Story by Russ Kaniuth.

The post What to Cut: Hava Ridge Jasper first appeared on Rock & Gem Magazine.

The Bloody Basin Road is a long road off the beaten path running through Yavapai County in the Tonto National Forest. It got its name from an event in March 1873, where the U.S. Army had a confrontation with several Apaches, who lost their lives in the attack.

Where to Find Bloody Basin Plume Agate

Bloody Basin Plume agate has been found at various sites there. This material is well known for its various fiery colorations of yellow, orange and red with varying patterns of billowing plumes to moss. Though this material is getting scarce, it still can be found in the marketplace at shows and online sales.

How to Pick Bloody Basin Plume Agate Rough

Picking out rough isn’t difficult. Usually, the raw material will show its patterns when the stone is wet. This material can also tend to be a bit vuggy. It’s easy to work around vugs or work them into your cabochon designs. Most lapidaries seek out the plume agate, but the moss can be quite beautiful as well because it’s full of vibrant color.

Slabbing the Material

Before you start slabbing this material, look for the orientation of the plume going from south to north. This is the direction you want to show so that your slabs reveal the plume growth patterns. No two cuts are ever the same, the patterns are ever-changing throughout the stone.

Once your slabs are cut, and you see desirable patterns you want to cut, then take the time to examine the material for the pitting. Either stabilize the slabs to fill them in or continue to trim out your preforms keeping the material’s natural integrity. The pits are essentially cosmetic and will not affect the stability of the stone. It’s a matter of choice.

Cutting & Finishing

Once your slabs are cut, and you marked your designs to trim out the preforms, the cabbing process is fairly easy. The agate is about a 6.5 on the Moh’s scale. You’ll need to start on a course 80 grit steel wheel to shape and dome the cabs. From here, I like to use a 60-grit soft resin wheel to quickly smooth the top and remove any flat spots and deep scratches. From this point, move onto either a 140 or 220 soft resin wheel. If your setup only has a 220 steel wheel, this is fine. You will just have to spend a little extra time on the 280 soft resin wheel removing scratches.

Once you’ve reached the 280, this is where you need to take your time and continually dry the cab off in the process to examine for any residual scratches or open pits. The pits are usually very small or micro. If you want a smooth surface cab and you have stabilized your material ahead of time, this is where you want to stop and examine if the epoxy has soaked in enough.

If new pits have revealed themselves, fill them in now. Move on to the 600-grit to, at least, the 14k grit wheel. This should yield a beautifully polished cab. If you desire to gain a little extra mirror polish, you can either use cerium oxide on a damp leather buff, or Zam polishing compound with a polishing Dremel bit.

This What to Cut column about Bloody Basin plume agate varieties previously appeared in Rock & Gem magazine. Click here to subscribe. Story by Russ Kaniuth.

The post Bloody Basin Plume Agate first appeared on Rock & Gem Magazine.