Diamonds:Gemology

Don't be fooled by this new diamond simulant

You've heard it before, but synthetic moissanite will be available sometime this year, assures C3 Inc., the North Carolina company that's producing and stockpiling the diamond lookalike. The gems will range from 3 points to a half-carat. "Synthetic moissanite should retail from 5% to 10% of the cost of a natural diamond," says Jeff Hunter, C3 president. That's between $300 and $500 per carat. Though at first production was limited to small crystals, larger crystals are now possible, allowing C3 to reduce manufacturing costs while increasing the volume of gemstones produced from each crystal by more than 100%.

Take Care
Synthetic moissanite can fool conventional diamond testers, which evaluate a stone's thermal conductivity. Unlike other diamond simulants, moissanite is thermally conductive.

In broadcasts on the Discovery Channel that ran late last year, several U.S. jewelers and appraisers thought moissannite was natural diamond. Those tests sent shivers up the spines of those in the diamond jewelry business. De Beers issued a memo, immediately responding to concerned sightholders, explaining the broadcast and its implications. The memo included two pages of questions and answers about moissanite.

Separately, the Gemological Institute of America published details of its exhaustive study of moissanite in the Fall 1997 issue of Gems and Gemology.

Despite the market test's ominous results, there are standard gemological tests that separate moissanite from diamond. In addition, C3 has developed a new diamond tester that was being market-tested at press time. The new detector bases decisions on stone origin on optical characteristics rather than thermal conductivity. The tester should cost less than $500.

Until you get your hands on the tester or if you're concerned that synthetic moissanite might have made it to your inventory, look for the following telltale moissanite signs that can be detected through conventional means:

• It's doubly refractive (2.65-2.69). Diamond's refractive index is 2.42. With magnification, you can make out a faint "doubling of the image" in the pavilion facet junctions looking through the table of the stone. Diamond facet junctions stay single.
• Some moissanite samples have unique whitish, ribbon-like inclusions under magnification. These are not found in diamonds.
• A hardness of about 9.25. Diamond's hardness is 10.0. Moissanite is essentially a form of silicon carbide.
• Most samples have tinges of yellow, green or gray though producers have been working hard to eliminate them. Completely colorless synthetic mois-sanite is extremely rare, though the larger sizes - around a half-carat - have less-visible shading.

   

Learning More
C3 has taken the task of alerting the industry to the presence of synthetic moissanite quite seriously.

Hunter has led the charge to educate jewelers, appraisers and educators about moissanite. "We have crossed the country speaking to appraisal organizations, GIA Alumni chapters and such - people who really need to know," he says. "We have also supported GIA's efforts in conducting a full study of laboratory-grown moissanite."

by Robert Weldon, G.G.

Synthetic moissanite, a new and convincing diamond simulant, should be on the market by next month. Gems and photo courtesy of C3 Inc., Raleigh, NC.

• Home • Ask the Expert • Brainstorm • Stats • Site of the Week • Consumer Press Scan

• Your Business On-Line • Calendar • Magazine & Site Archives • Staff • Site Map

• Professional Jeweler Events • Guide to Electronic Services

• Classified On-Line • JA Certification Study Session