Professional Jeweler Archive: Stone Fortress

September 2002

Gemstones & Pearls/News


Stone Fortress

Columbia Gem House aims to spin dollars out of an attractive green gem with an interesting new name


What do you get when you mix a bright green peridot with a blue-green tourmaline? Tashmarine,™ of course.

Eric Braunwart says his company, Columbia Gem House, Vancouver, WA, chose the mellifluous name and hopes that with proper marketing, good supply and marketable sizes, the gem is on a fast track to join tanzanite, tsavorite and Paraíba tourmaline in a select group of newer world-class gemstones.

Gemologically, the gem is diopside, and it’s from a deposit near Tashkent in eastern Uzbekistan. Diopside, mostly originating in Russia, has been gaining popularity as a gem in recent years, particularly because its deep green is reminiscent of the finest green tourmaline – at a fraction of the price. A recent issue of The Guide lists the wholesale price of extra fine chrome green tourmaline in the 5-10-ct. range at $600-900 per carat. Chrome diopside of a similar size, clarity and color is $50-80 per carat.

Diopside is a lot softer though, measuring 5.5 on the Mohs hardness scale, similar to tanzanite. Gemologists are quick to point also to the gem’s weakness: cleavage planes. Improperly cut or set, or if dealt a hard knock, the gem is prone to sudden parting along these planes. Columbia Gem House found the gem shows great resistance to wear and tear if its table is about 20&Mac251; diagonal to the cleavage plane. “It can be put in ultrasonic cleaners or steamed without any concern,” says Braunwart.

The company also conducted other stress tests – including heat (up to 1,000&Mac251;) and acid pickling overnight – and found they had no effect on the gemstones. “We’ve also tried to duplicate the setting environments Tashmarine is likely to encounter and have had a chipping rate of zero,” he says.

The gem is neither treated nor enhanced in any way. “The green is exactly as it comes from the earth,” he says.

Diopside Differences

Tashmarine is far lighter and brighter than most other fine and commercial diopside. Columbia Gem House is cutting the gem to further boost that advantage. Renowned gem cutter Richard Homer facets the larger gems, adding concave facets to increase brilliance and dispersion. Smaller gems (up to 7 carats for manufacturers) are faceted in large quantities to optimize color and light return in calibrated sizes.

Tashmarine has met with a warm retail welcome. “We’re very excited about this gem,” says Michael Valitutti, G.G., a buyer for Nathan Hennick & Co., Downsview, Ontario, Canada. “Where else in this industry can you find something totally natural of this size, color and clarity? It also has a super name that will stick with consumers.”

Braunwart says coming up with the name was a challenge. Tashmarine comes from the name Tashkent, which means stone fortress in the local Tajik language, and marine, which refers to its ocean-like color. “Tash, or Natasha, our daughter’s name, is one we also wanted to associate with this beautiful new gemstone,” he says.

• Columbia Gem House, Vancouver, WA; (800) 888-2444 or (360) 514-0569, mrkt@columbiagemhouse .com.

– by Robert Weldon, G.G.

A 32.57-ct Tashmarine with concave faceting, cut by Richard Homer.

Photo by Bart Curren.

Copyright © 2002 by Bond Communications