What to Cut | Rock & Gem Magazine https://www.rockngem.com Rock & Gem Magazine Mon, 27 Nov 2023 16:42:03 +0000 en-US hourly 1 https://wordpress.org/?v=6.3.2 https://www.rockngem.com/wp-content/uploads/2018/10/cropped-Favicon-32x32.jpg What to Cut | Rock & Gem Magazine https://www.rockngem.com 32 32 Seraphinite – What to Cut https://www.rockngem.com/seraphinite-what-to-cut/ Mon, 27 Nov 2023 11:00:50 +0000 https://www.rockngem.com/?p=23024 Seraphinite is a form of clinochlore, a member of the chlorite group. It is only found in the Lake Baikal region of eastern Siberia. Seraphinite acquired its name after Seraphim, the biblical highest order of angels, because of its shimmery, feather-like appearance. Seraphinite Properties The mica inclusions give the stone wonderful chatoyancy. The inclusions grow […]

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

]]>
Seraphinite is a form of clinochlore, a member of the chlorite group. It is only found in the Lake Baikal region of eastern Siberia. Seraphinite acquired its name after Seraphim, the biblical highest order of angels, because of its shimmery, feather-like appearance.

seraphinite
Pin this post to save this information for later.

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.

seraphiniteCutting 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.

seraphiniteRemember, 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.

]]>
Dumortierite: What to Cut https://www.rockngem.com/dumortierite-what-to-cut/ Mon, 27 Nov 2023 11:00:33 +0000 https://www.rockngem.com/?p=23026 Dumortierite was originally discovered in the late 1800s by a French mineralogist, who named it after paleontologist, Eugene Dumortier. 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 […]

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

]]>
Dumortierite was originally discovered in the late 1800s by a French mineralogist, who named it after paleontologist, Eugene Dumortier.

dumortierite
Pin this post to save this information for later.

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.

dumortieriteCutting 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.

dumortieriteCabbing 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.

]]>
Orbicular Bloodstone Jasper https://www.rockngem.com/orbicular-bloodstone-jasper/ Mon, 03 Apr 2023 10:00:56 +0000 https://www.rockngem.com/?p=11405 Orbicular bloodstone jasper looks like a cross between fancy jasper and ocean jasper. It is quite appealing with its bright reds, oranges, and greens, not to mention, the orbs. Since this material is full of color blends and patterns, it creates a natural canvas to use in designing cabochons. My son Ben, for example, likes […]

The post Orbicular Bloodstone Jasper first appeared on Rock & Gem Magazine.

]]>
Orbicular bloodstone jasper looks like a cross between fancy jasper and ocean jasper. It is quite appealing with its bright reds, oranges, and greens, not to mention, the orbs.

Since this material is full of color blends and patterns, it creates a natural canvas to use in designing cabochons. My son Ben, for example, likes to utilize the color blends to combine hearts into one cab as if the hearts are blending into one.

Buying Orbicular Bloodstone Jasper

orbicular-bloodstone-jasper
Pin this post to save this information for later.

Finding this material is relatively easy. There are several sellers on Facebook — in the Slab Depot group, and on eBay.

When buying rough, you can usually see all the colors from the outside, which helps in deciding whether it has the sought-after colors. One thing to note, this material is a rather hard jasper and tends to have a few fractures. Usually, when I know rough may contain fractures, I tend to buy smaller-sized chunks instead of large pieces. I do this just in case the section I purchase contains many hidden fractures that I’ll have to work around during the cabbing process.

This variation of bloodstone might be a material that is best to purchase in pre-cut slabs so that you can see the full pattern and color array immediately.

How to Slab Orbicular Bloodstone Jasper

orbicular-bloodstone-jasperWhen slabbing this material, there is no right or wrong way to load the vice. One method is to study the color patterns and try and cut in the direction you feel will best yield the desired patterns. If the piece is large enough, another option is to cut down the center and evaluate the pattern and then load the halves into the saw again, in a different direction. Either way, your study of the patterns and colors will help you bring out the best in each piece.

Another helpful technique when working with bloodstone is to bench test each piece by tapping slightly on a table or workbench and listening for fractures. If it’s solid, draw up templates and trim them out.

As you move into the next phase of cabbing, you’ll find the material is standard to most jaspers. However, because of the hardness and highly silicated composition, it is a jasper that tends to chip easily, especially on the bottom edge of the courser grit wheels. It’s best to trim out preforms just a little larger and then grind away excess on a smoother grit wheel, to avoid chipping.

Finishing Up

orbicular-bloodstone-jasperAs they say, patience is a virtue, and you’ll need a lot of it as you work with this material, because it can be incredibly challenging to remove all of the scratches by the 280 grit stage.

At the point where there are no scratches left, or there is no way they will be removed with the remaining wheels, proceed with your routine and polishing stages. By the time you reach the 14k grit wheel, it should have a fantastic mirror polish. To enhance the shine, you can use either cerium oxide on a leather buff or buff with a small amount of Zam compound.

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

The post Orbicular Bloodstone Jasper first appeared on Rock & Gem Magazine.

]]>
What to Cut: Fallen Tree Thundereggs https://www.rockngem.com/fallen-tree-thundereggs/ Mon, 27 Feb 2023 11:00:45 +0000 https://www.rockngem.com/?p=19243 What are fallen tree thundereggs? Somewhere in the mid-1960s in the Ochoco Mountains near Prineville, Oregon, Leonard “Kop” Kopcinski, owner of the Lucky Strike & Valley View Mines, stumbled upon a windblown “fallen tree” with the large roots exposed. Within the roots, he discovered a few thundereggs, which lead him to further explore that area. […]

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

]]>
What are fallen tree thundereggs? Somewhere in the mid-1960s in the Ochoco Mountains near Prineville, Oregon, Leonard “Kop” Kopcinski, owner of the Lucky Strike & Valley View Mines, stumbled upon a windblown “fallen tree” with the large roots exposed.

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
Pin this post to save this information for later.

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.

fallen-tree-thundereggsCabbing 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.

]]>
Lakota Blue Ice Agate https://www.rockngem.com/lakota-blue-ice-agate/ Mon, 26 Dec 2022 11:00:33 +0000 https://www.rockngem.com/?p=16429 Lakota Blue Ice Agate is a beautiful chalcedony with blue hues that catches your attention when you see it cut into cabochons. It comes from the Pine Ridge Lakota Reservation on privately owned land. About Lakota Blue Ice Agate When speaking with Mike Joebgen, who’s been allowed to collect there over the years with a […]

The post Lakota Blue Ice Agate first appeared on Rock & Gem Magazine.

]]>
Lakota Blue Ice Agate is a beautiful chalcedony with blue hues that catches your attention when you see it cut into cabochons. It comes from the Pine Ridge Lakota Reservation on privately owned land.

About Lakota Blue Ice Agate

When speaking with Mike Joebgen, who’s been allowed to collect there over the years with a Lakota escort and friend, he said this agate comes in a seam in the White River Drainage in the Badlands. There is an abundance of blue chalcedony in this region, but only this one type that is thick and large enough to make cabochons. Since this area has a significant amount of erosion, they are not allowed to dig. Instead, they wait for the weather to erode a certain amount that they can collect each winter.

lakota-blue-ice-agate
Pin this post to save this information for later.

Since this is a seam agate, it usually comes in one-quarter to three-quarter-inch thick small pieces. The best way to work with this material is to cut down the middle and dome from the outer edges grinding through the rough naturally exposed surface areas. If you can get ahold of a thicker piece, then you can try cutting off the outer rough edges and down the middle to get two nice slabs to start your work. Almost 100 percent of this material is useable since the color flows through the entire slab. From what I’ve experienced, there aren’t many, if any, fractures to work around. Working with this material is a pleasure!

Cabbing

To start your cabbing process, trim out your preforms and start grinding them on the 80-grit steel wheel leaving at least .5 millimeters around the edges in case it chips on the backside. Start to dome the top. As you progress to the 220-grit stage, you can trim your preform in a little closer to alleviate any chips on the back outer edges and smooth out the top dome. When moving on to the soft resin wheels, it’s always best to have good water flow to keep the cabochon cool and not generate heat from friction.

Chalcedony can easily start a small fracture that will tend to travel in your work as you progress. Much like a small chip in the windshield, it will generally travel and get larger.

lakota-blue-ice-agateOnce you’ve reached the 280-grit soft resin wheel, you can put all your time and effort into smoothing everything out and making sure no scratches remain. A good light source is important, especially when you are dealing with single-colored cabs, for hunting down any flaws before moving forward. Once you’ve obtained a smooth scratch-free surface, the rest should be easy. By the time you’ve finished on the

600-grit soft resin wheel, it will already be taking a nice polish and displaying the deep blue color. Continue to the 14k-grit wheel, and for most people, this is a good place to stop. You should have a beautifully polished cab ready to set into jewelry. If you want to attempt to garner a more mirror-polished stone, you can gently use a leather buffing wheel with cerium oxide, but try not to overheat the stone and chance adding fractures.

This What to Cut column about Lakota Blue Ice Agate previously appeared in Rock & Gem magazine. Click here to subscribe. Story by Russ Kaniuth.

The post Lakota Blue Ice Agate first appeared on Rock & Gem Magazine.

]]>
What to Cut: Pink Natrolite https://www.rockngem.com/what-to-cut-pink-natrolite/ Mon, 21 Nov 2022 11:00:18 +0000 https://www.rockngem.com/?p=14864 Pink natrolite comes from Indonesia, where it’s being mined as seam material. It’s botryoidal on one side, attaching to its basalt host stone, and has radial crystals tinted by iron, giving it that pink larimar appearance on the opposite side. Larimar has been an exceedingly popular material for quite some time now. As a new […]

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

]]>
Pink natrolite comes from Indonesia, where it’s being mined as seam material. It’s botryoidal on one side, attaching to its basalt host stone, and has radial crystals tinted by iron, giving it that pink larimar appearance on the opposite side. Larimar has been an exceedingly popular material for quite some time now. As a new type of stone with an equivalent appearance with a pink-rose color, natrolite enjoyed great popularity in a hurry.

pink-natrolite
Pin this post to save this information for later.

Where to Find Pink Natrolite

Pink natrolite is easily found. It is sold at rock shows and can also be found online. Most of this material is smaller-sized pieces under a couple of inches in either direction and relatively soft, about 4.5 on the Mohs scale. The one thing to look for when shopping for this material other than the pattern is its thickness. Always look at both sides and make mental notes of whether or not there will be enough material for a cab after the botryoidal backside has been sanded down flat.

Since this is a seam material, you won’t have to do any slab cutting. Instead, you’ll have to trim out your preforms and then sand the backside. This material comes quite often in curled pieces, not always flat, so you’ll have to make adjustments as to how to trim each preform so that you can get a flat-backed cab.

Cabbing Pink Natrolite

pink-natroliteOnce you have your preforms cut out and are ready to cab, natrolite is fairly easy to cab. Though it looks like larimar, it’s much softer and doesn’t break apart as larimar does. So, start on an 80-grit steel wheel to shape your cabs. Go lightly at first, get a feel for the hardness of the material, and then start doming your cab.

Many people like to use 220 “steel” wheels in their setup, but I like to use 140 soft resin diamond wheels before moving on to the 280 grit. It quickly removes deep scratches and takes much of the hard work away so that by the time you are ready to move on to the 280, the majority of your work is already done. At the 280 grit stage, this is where you need to make sure all the scratches are completely gone before moving on.

Checking Scratches & Finishing Up

pink-natroliteWith this material, it can be very difficult to see scratches due to the white coloring and radial crystal patterns, so it’s best to have a good light source in your shop and to dry off the cab thoroughly to see if the surface is scratch-free.

By the time you finish the 600 grit stage, you’ll notice a nice polish already appearing; it doesn’t take much to get a brilliant mirror polish on natrolite. Continue to the 1200 and up to 14k grit. From here, you shouldn’t have to go any further, and this should yield a beautifully polished cab.

This story about crystallized fossil clams appeared in Rock & Gem magazine. Click here to subscribe. Story by Russ Kaniuth.

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

]]>
What to Cut: Chrysoprase https://www.rockngem.com/what-to-cut-chrysoprase-among-oldest-semiprecious-gemstones/ Mon, 11 Jul 2022 10:00:18 +0000 https://www.rockngem.com/?p=13253 Chrysoprase is the outstandingly beautiful apple green stone that really makes heads turn. Chrysoprase is a chalcedony mixed with nickel, which gives it that gorgeous gemmy green color. It’s believed to be one of the oldest semiprecious gemstones highly prized by many, including the Romans, Greeks, and Egyptians. It was also very popular in the […]

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

]]>
Chrysoprase is the outstandingly beautiful apple green stone that really makes heads turn. Chrysoprase is a chalcedony mixed with nickel, which gives it that gorgeous gemmy green color. It’s believed to be one of the oldest semiprecious gemstones highly prized by many, including the Romans, Greeks, and Egyptians. It was also very popular in the Victorian period when it was used as cameos and cabochons.

Chrysoprase Legend

There’s also a legendary tale about Alexander the Great, who believed he gained tremendous wisdom from this stone, and as such, wore it on his belt into each battle. That was until one day while crossing a river, he was struck by a snake, which caused the stone to be knocked off his belt and fall into the river. Unable to find and recover the stone, according to the tale, he never won another battle.

Where to Find Chrysoprase

Pin this post to save this information for later.

Chrysoprase is found in several places on earth, including Germany, the United States, and Madagascar. However, the most known locality in modern times is the Marlborough region in Queensland, Australia. This stone is getting a bit scarce to find in higher grade material in larger size pieces, and pricing reflects that in the marketplace. Grading is also something to carefully consider when buying this material. High-grade specimens will be a solid color with no blemishes or inclusions and are highly sought after, so expect a much higher price when shopping for rough or slabs that fall into this category. There are other colors of chrysoprase, such as citron/lemon, and a pale variation from Indonesia.

Purchasing Material

When buying rough, it can be tricky to find large enough seams that don’t curl up in many areas (like a potato chip). This condition makes it a challenge to slab, so be prepared to hunt through substantial pieces to find a few that will yield a large enough area in the slab to cut cabochons. Sometimes you might end up buying thin seams and have to grind the top and bottom portions to gain enough space to cab. Since chrysoprase is an exceedingly hard material, ranking at a 6.5 to 7 on the Moh’s scale, it is best to hold off proceeding until you have changed your blades and wheels. I can’t express how valuable a fresh set of wheels are when working on this material.

Grading is also something to carefully consider when buying this material. High-grade specimens will be a solid color with no blemishes or inclusions and are highly sought after.

Cabbing Chrysoprase

When cabbing chrysoprase, a traditional six-wheel set up will work just fine, but if you can swap around the wheels, I highly suggest starting on an 80 grit steel wheel, then smooth it out on a 60 grit soft resin wheel. This approach will reduce the time and effort it usually takes when working on a chalcedony that is this hard. After smoothing out the edges and doming the cab, I like to move onto a 140 grit soft resin wheel, which removes all the deep scratches and makes it easier to finish on the 280 grit wheel and progress forward. While working the cab on the 280 soft resin wheel, you can continue to check for any existing scratches. It would be best if you did not move forward at this point until the scratches are gone.

chrysopraseOne helpful trick to use at this point is to quickly run the cab over the 1200 grit wheel and then dry the cab completely. Being a solid color stone, if any scratches still exist, they will immediately show themselves by using the 1200 wheel. Once all the scratches are gone, and you can move forward, run the course like any other agate you cab and finish on a 14,000 grit soft resin wheel, or 50k if you have it.

Finishing Up

At this point in the process, your chrysoprase cab should render a brilliant glossy finish. You can use a small amount of cerium oxide on a leather buffing wheel to obtain a more mirror finish, but be cautious not to heat the cab in the process, as it may fracture from the heat generated.

Sometimes, leaving well enough alone is the best thing to do.

This What to Cut column about chrysoprase previously appeared in Rock & Gem magazine. Click here to subscribe! Story and photos by Russ Kaniuth.

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

]]>
What to Cut: Cold Mountain Thundereggs https://www.rockngem.com/what-to-cut-cold-mountain-thunder-eggs/ Mon, 02 May 2022 10:00:41 +0000 https://www.rockngem.com/?p=8545 Cold Mountain thundereggs come from the Sierra Mountains between the cities of Aguascalientes and Zacatecas, Mexico. When you hear the word thundereggs, most people quickly associate them with baseball size geode-type stones filled with agate. In this case, this material is just a slight bit different. This material looks like a bunch of golf balls […]

The post What to Cut: Cold Mountain Thundereggs first appeared on Rock & Gem Magazine.

]]>
Cold Mountain thundereggs come from the Sierra Mountains between the cities of Aguascalientes and Zacatecas, Mexico.

When you hear the word thundereggs, most people quickly associate them with baseball size geode-type stones filled with agate. In this case, this material is just a slight bit different. This material looks like a bunch of golf balls and marbles all clustered together in a big muddy clump! Once you cut one open though, you will see all the beauty in it.

Cold Mountain Thundereggs vs. Butterfly Jasper

cold-mountain-thundereggsThis material resembles Butterfly jasper quite a bit but certainly has its own beautiful characteristics. The rhyolite is full of earthy colors, and the orbs have fractal patterns with rivers of agate running through them.

When buying rough, you won’t really know what’s inside until you cut it. You can look for pieces with more orbs showing on the outside, and some with possible pieces broken off so you can see the patterns inside. Each piece will always be different, there will be no two slabs the same.

When cutting slabs, there is no real direction to clamp the stone into the saw for a certain pattern, so position the material in the vice that best fits the saw. Because of the awkward round shapes the rough comes in, sometimes using wood wedges to secure the stone in the vice is advisable.

Testing for Fractures Pays Off

Once your slabs are cut, and it’s time to draw out your cab patterns, test each slab first for possible fractures that will break apart. It’s better to find out now than later down the line that there is a fracture. Flexing the slab in your hands or tapping it lightly against the bench will usually tell you if the slab will be stable or not. The fractal patterns, orbs and rivers of agate will give you all sorts of abstract patterns to work from to create gorgeous designs.

Cabbing this material is generally pretty easy, it’s really not much different from any other rhyolite or jasper. I would guess the hardness on the Moh’s scale to be around a 5.5, so start on an 80 grit to shape your preform and start your dome. Though there are different minerals involved in the material, they don’t differ too much in hardness so you shouldn’t have too much trouble with undercutting, but I would suggest smoothing out the dome and removing as many of the scratches on the 220 grit wheel as possible.

From there, let the 280 grit wheel do the work, smooth out the cab, and make sure to remove any remaining scratches at this stage before moving on. By the time you reach the 600 grit wheel, you will see how quickly the rhyolite starts to polish up. Continue the cabbing process as usual, most might finish at the 14k grit wheel, which will leave you with a nice glossy polish. However, if you have a 50k grit wheel in your setup, you will achieve a mirror polish.

Skip Polishing Compounds When Fissures Are Present

cold-mountain-thundereggs
Pin this post to save this information for later.

Since this material contains agate and is comprised of several minerals, you might find small drusy vugs within the agate or small fissure openings along some of the patterns where they bud up against each other, this is why I wouldn’t suggest using polishing compounds. The compounds will fill these areas in and make it very tough to get it out.

The final polish usually looks best from what you’ve achieved on the wheels. This material and many other Mexican stones are readily available through the J H Kalmore Company on Facebook.

This What to Cut column about Cold Mountain thundereggs previously appeared in Rock & Gem magazine. Click here to subscribe! Story and photos by Russ Kaniuth.

The post What to Cut: Cold Mountain Thundereggs first appeared on Rock & Gem Magazine.

]]>
Mexican Purple Passion Agate https://www.rockngem.com/cutting-mexican-purple-passion-agate/ Mon, 02 May 2022 10:00:20 +0000 https://www.rockngem.com/?p=11996 Purple passion agate wide array of colors ranging from soft pink to lavender to deep dark purple and flowering patterns that largely resemble Agua Nueva agate. This agate seems to come in nodules, but actually, it’s more of a seam agate and usually comes in smaller chunks. Purple Passion Agate – Savvy Selecting What are […]

The post Mexican Purple Passion Agate first appeared on Rock & Gem Magazine.

]]>
Purple passion agate wide array of colors ranging from soft pink to lavender to deep dark purple and flowering patterns that largely resemble Agua Nueva agate. This agate seems to come in nodules, but actually, it’s more of a seam agate and usually comes in smaller chunks.

Purple Passion Agate – Savvy Selecting

purple-passion-agateWhat are agates? There are many agates to choose from like bubblegum agate and glacier ice agate. When shopping for Purple Passion, there are a few variances to look for in the rough. Some will include quartz as their matrix, with some fantastic purple agate swirls running through the center. Additionally, other chunks will be encrusted with their host rock and surrounded by the flowering patterns, much like you see in Agua Nueva agate.

Helpful Hint: It’s always best to wet this material to see its colors and whether it will have nice patterns running through it.

Purple Passion Agate – Finding Fractures

One thing to look out for when working with Purple Passion is the presence of fractures running through the fortification at the center of each piece. If you buy your material all slabbed up or at least face cut, to begin with, you will see if the center has these fractures. If you come across pieces with fractures, it’s certainly not the end of the world, and can be easily worked around, but it’s nice to find the high-grade pieces that are unblemished.

purple-passion-agateOther things to watch for are Purple Passion with spots of agate in the host rock. While this does provide a beautiful effect when designing cabs, it will also give you a challenge with varying hardnesses, as the host rock is much softer than the agate and tends to undercut.

When beginning to cut slabs, it’s best to wet your material, in order to determine which face to start. Since most of this material is smaller in size, I suggest hand cutting on a 10-inch trim saw. Hand-cutting allows you to see if it yields the patterns you are looking for or gives you the ability to easily change directions and cut from other angles without reloading a vice each time. Generally, since this material runs in seams, it’s easy to find a good starting point and continue slabbing in the same direction.

Successful Steps for Cutting Cabs

Once your slabs are cut and prepared to trim out your preforms, bench test your pieces to ensure you don’t run into any hidden fractures that could fall apart in the beginning stages of cabbing.

purple-passion-agate
Pin this post to save this information for later.

Lightly tap the slabs on the workbench or a hard surface, and check each piece’s stability. I generally start on the 80 grit wheel to shape and dome each preform.

After you have your preform cab shaped, you can start smoothing it out on a 220 grit steel wheel, or I like to use a 140 grit soft resin wheel on agates instead. (The 140 grit wheel smoothly removes all the deep scratches from the 80 grit and will continue to remove material while smoothing out the dome and edges, leaving very little work for the 280 grit wheel.)

Once you move to the 280, all you have to do is remove any existing scratches. Be sure to have a good light source nearby, so when you occasionally dry off your cab and check for any existing scratches, you will be able to see them in the darker colored areas that usually are hard to see. If you miss them at this stage, they will guarantee to show up once you go further and start polishing.

Once all the scratches are gone from the 280 stage, move to the 600 grit wheel and start polishing. At this point, dry the cab and check once more for scratches, and it should already look as if it’s polished. Keep in mind, if any scratches exist, they will show up at this point; if there are none, you are good to continue to the polishing stages by moving on to the 1200 grit wheel.

Finishing Up

Purple Passion is a great agate to work with and doesn’t need any special tricks to bring the polish to a mirror shine, you can finish at 8k grit or 14k grit, and that will give you a beautiful cab.

Polishing Tip: If you desire a mirrored polish, cerium oxide on a leather buff will certainly do the trick but go slow and don’t allow the stone to heat up, because it could very well fracture.

This What to Cut column about purple passion agate appeared in Rock & Gem magazine. Click here to subscribe! Story by Russ Kaniuth.

The post Mexican Purple Passion Agate first appeared on Rock & Gem Magazine.

]]>
What to Cut: Aurora Opal https://www.rockngem.com/what-to-cut-aurora-opal/ Mon, 25 Apr 2022 10:00:21 +0000 http://www.rockngem.com/?p=6914 Aurora Opal is a homogeneously crystalized, synthetic, impregnated opal. Roy Goldberg, at Aurora Opals, describes this material as irregular and fine crystalline, with nondirectional, multicolor swirls, with green, orange, blue and red being the dominant colors in the spectrum. I see lots of new materials being introduced into the lapidary world. There have always been […]

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

]]>
Aurora Opal is a homogeneously crystalized, synthetic, impregnated opal. Roy Goldberg, at Aurora Opals, describes this material as irregular and fine crystalline, with nondirectional, multicolor swirls, with green, orange, blue and red being the dominant colors in the spectrum.

I see lots of new materials being introduced into the lapidary world. There have always been a large number of “purists” who do not like to work with anything that is not a natural stone, but many like myself feel that trying something new can be fun, adventurous and challenging.

Intrigued by Synthetic Opal

After reading through Roy’s website and admiring all the various pictures, I was definitely intrigued enough to try this material.

aurora-opal
Pin this post to save this information for later.

I purchased the red and white variations to try first and was just amazed when the material arrived. Whether outdoors in natural sunlight or indoors, the play of color in this material was just outstanding!

To begin with, I cut the blocks I received from top to bottom into slabs about 6 mm thick. Usually, when cutting smaller items, I use a 10-inch trim saw, running just with water. Since Aurora Opal is a resin-based material, I don’t see any issues cutting it with either water or oil in the saw.

When you have cut your slabs and preform shapes and are ready to start the cabbing process, remember that this material is only four on the Mohs Scale of Hardness, so you definitely want to start on a less coarse-grit wheel; I suggest the 220 grit wheel.

Committed to the Drying Process

aurora-opalWith all resin-based materials, it’s important to dry off the cab at every interval of the process to check for any deep scratches from the prior stage. Micro swirl marks are quite common with synthetic materials but don’t be too alarmed in the earlier stages, as they will work themselves out as you go.

I made several cabs from this material, experimenting with different dome heights to see if there was any difference in color play, and in my opinion, higher domes catch the light from all angles, making the cab more eye-catching when set into a finished jewelry piece.

You can also experiment with the color swirl angles. They seem to run more horizontally in the tray, so when you get your blocks cut down, try orientating some horizontally and some vertically for variety.

Cabbing Aurora Opal

aurora-opalThe cabbing process is quite simple, starting with 220 grit and ending with 14000 grit. Higher-grit wheels will definitely give you a glossier shine, but they are not a necessity. Once I finished on the 50000 grit wheel, the cabs were perfectly ready to be set into jewelry.

I don’t think any further polishing compounds are necessary, but if I were to attempt to go a step farther, I would use white rouge lightly to finish the polishing. Be extremely careful not to heat the stone up while attempting to polish though—this is a resin, and will melt if heated up too much. Then it’s back to the drawing board!

This What to Cut column about aurora opal previously appeared in Rock & Gem magazine. Click here to subscribe! Story and photos by Russ Kaniuth.

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

]]>