10+ Way Cool Cabochons from Around the World Seen in Tucson
These “ghost quartz” amethyst slabs from Arizona are just waiting to be cut into cabochons by the guy who dug this up. Seen here showing it off at the Kino Gem and Mineral Show: John Heusler of Slabs to Cabs was happy to let me take a pic. The white, cityscape-like patterns are the result of quartz crystals that have disappeared: all that’s left is the ghostly outline in chalcedony, a noncrystalline form of quartz.
Even locals call it “the gem show,” although the 40 or more different venues that spring up during the first half of February in Tucson, Arizona, offer minerals, fossils, beads, jewelry, related tools and supplies, and more besides. Since its inception 63 years ago as a weekend club mineral show, it’s become the world’s foremost mineral and fossil show. And the greatest gem trade show on earth.
All of it is my favorite. Loose cut stones deserve special attention in my book though. Among those, it’s the interesting and unusual in cut, color, and pattern that attract me. Very often those materials are cut as cabochons, so here are just a few of the cabs that caught my eye this year, pretty much just in the order I happened upon them.
1 Charoite from Russia
Purple is my first favorite color and this gem material is a dandy. At its best, it’s a rich purple swirled with black, white, and the occasional pale peachy hue. At its very best, those swirly patches also exhibit that mesmerizing sheen of light called chatoyance (familiar to most people in tiger-eye). Charoite is mined from one locality in Russia, near the Chara River in Siberia. Since it was first described in 1978, supplies have varied. This year what I saw was lovely, with good color, some with chatoyance, as in this sampling of cabochons on display in the courtyard at the Pueblo Show.
2 Drusy Agate from Brazil
A source for many beautiful agates, Brazil is also the source for much drusy agate. That is, agate (a form of quartz) covered with tiny, colorless quartz crystals. In the most dramatic material, the underlying agate has some interesting color or pattern, and the crystal coating is small, uniform, and clean, which makes a stone cut from it sparkle like snow in bright sunlight. This cabochon was available at the Pueblo Show and cut by Greg Genovese, who frequently travels to the mines in Brazil (and elsewhere) to get the perfect rough.
3 Composite, USA to Down Under
Exhibiting at the Gem & Jewelry Exchange (GJX), gem carver Steve Walters often combines more than one material in his cabochons. This marquise shaped cab includes pieces of Montana agate, some with gold run through a rolling mill to create the pattern, and Australian matrix opal. The bands of agate colors, patchy gold, and the pinpoints of the opal’s “fire” or play-of-color give the piece a rich contrast.
4 Australian Opal
Gene McDevitt mines for, cuts, and wholesales opal cabochons from Australia, a place well-known as a producer of opal. This pair of boulder opal cabs is from Koroit in Queensland. The blues and greens of the opal light up against the tan matrix, or surrounding rock, in which the opal is found. Boulder opal often has great colors and life but occurs in thin seams and is typically cut with the boulder surrounding it, hence the term. At the Gem & Jewelry Exchange (GJX).
5 Fossil Coral, Indonesia
Many shades of tan, buff, and peach appear in the fossil coral found in several areas in western Indonesia. The original coral has been replaced by quartz, very often the mineral that replaces once-living objects that become fossilized. Cut in cross section, the now agatized corals appear like flowers scattered across a gem’s surface. Seen at Tarak at the Gem & Jewelry Exchange (GJX).
6 Garnet, South Africa
If you’ve been a fan of gemstone cabochons for a long time you may recall an opaque to translucent material called Transvaal “jade,” actually a garnet that was typically green, often with some pink. At Donald K. Olson at the Gem & Jewelry Exchange, I saw this speckled white, bluish green, and black cabochon, also garnet (the black is chromite) from the Transvaal in northern South Africa.
7 Montana Agate
Agate is found in many places around the world. The distinct patterns of Montana agate are only part of what makes this agate special. It’s really known for taking an exceptionally good polish. Ask any lapidary who’s cut Montana agate, and he or she will tell you there is something different, something better, about this material. This set of Montana agates was on offer at Donald K. Olson at the Gem & Jewelry Exchange.
8 Petrified Oak, Oregon
Prized for its rich warm color and dramatic grain patterning, fossilized oak wood is known as golden oak. According to Barlows Gems, where I saw these cabs at the Arizona Mineral & Fossil Show, the material is from a Miocene-epoch petrified oak tree, making it about 15-30 million years old. It’s from the Stinking Water area of Oregon, which is well known to petrified wood fans.
9 Madagascar Jasper
Popularly known as ocean jasper, or Madagascar jasper as it’s found off the coast of that large island off the east coast of Africa, this jasper (an opaque form of quartz) is characterized by dots and circles and shades of pink, green, white, and tan. It’s also called orbicular jasper, which simply means it’s characterized by little orb-looking patterns.
10 Chalcedony from the Western US
Some people collect gems for their own sake, but mostly we buy stones to put them in jewelry. This bubbly-looking chalcedony (called botryoidal, meaning like a bunch of grapes) is just the kind of unusual form that jeweler and gem cutter Falk Burger of Hard Works is known for. “I bought the chalcedony from a rockhound in Quartzsite in the ‘80s. He collected it from pockets along the shore of a newly dammed lake in California or Oregon, I don’t remember,” Falk told me when I asked where this gem was from. Falk was showing in Tucson at the Arizona Mineral and Fossil Show. I saw this pendant created by Marcia Cook, with the cabochon set in 18K gold, at the Tucson Gem and Mineral Show. This is the name of the original Tucson Gem & Mineral Society show that launched the whole “Tucson show” that exists today.
11 Purple Chalcedony from Manakkara, Indonesia
Here’s Lapidary Journal Jewelry Artist Contributing Editor Lexi Erickson shopping at Fretz Tools at the Pueblo Show. And here she is wearing her Grape Chalcedony necklace (which appeared on the cover of the November 2016 issue). Lexi designed and made the piece using a cab from The Clam Shell, which had more of these cabs at their American Gem Trade Association (AGTA) show booth. Because of its purple color, this piece of botryoidal chalcedony (as above, meaning the form resembles a grape cluster) is very believable as the centerpiece of her grape-themed pendant, complete with silver and copper leaves and tendrils.
Lexi knows a lot about setting interesting and often irregular cabochon gems, especially in bezels. Bezels are the backbone of cab setting, and Lexi starts by giving you great pointers about picking out a cabochon. And not just for how it looks on the front but also how well cut it is for setting on the back and sides, and many other helpful hints as well. Whether you’ve just acquired a “collection” of cabs you’d like to set in jewelry or want to get started making cabochon jewelry now, Lexi’s best-selling video Metalsmith Essentials: Setting Stones with Bezels is a great place to start, and a great resource whenever you’re setting the coolest of cabochons.