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Synthetic Diamonds

For more on synthetic diamonds, order the back issue of Gems and
Gemology, Winter 1995, 9.95 ea. US, 14.00 elsewhere. Call
800.421.7250, x 202 (may not be the right number since they

It includes a pull out poster (which I think can be purchased
separately from the GIA bookstore catalog) on the charactaristics
of natural vs. synthetic diamonds.

Just like fracture-filling, once you know what to look for it’s
easy. Those interested in learning more about this kind of thing
could join GIA’s Alumni and Asssociates, which hosts meetings in
which they sometimes bring microscopes and sample stones. You
could also take a GIA seminar on the topic.

There are a number of ways to differentiate – it’s been two or
three years since the seminar – the main one I remember is an
octagonal shape (like a growth line) inside which indicates
synthetic. I looked around a bit for my poster on it – can’t
lay my hands on it just now.

I encourage everyone to buy the poster and/or the magazine and
read up on the subject. Anyone who buys or sells diamonds should
know how to do the separation, IMHO.

Like all of these things, it seems scary until you learn how to
tell them apart. Than, armed with knowledge, you’re prepared and

Chicago, Illinois, US


The Russians have been synthesizing diamond for quite a while now,
but not nearly as long as General Electric. That all-American company
has been using high-pressure techniques to manufacture
industrial-grade diamonds since 1955. So give us Yanks credit for
once, okay? Most of the Russian synthesis techniques are generally
based on American technology. The difference is that GE has been
content to produce smaller industrial diamonds until recently (it now
has the capability to make larger gem-grade stones, too, but I haven’t
seen signs of a marketing campaign) while the Russians have focused
their efforts on producing and marketing larger gems. The Chinese are
also synthesizing diamonds (they now produce the least expensive
industrial crystals in the world) and are doing work in all areas of
diamond synthesis and treatment. (Henri Moissan, the namesake of
diamond substitute Moissanite – synthetic hexagonal silicon carbide
– claimed to have discovered a diamond synthesis process in 1896 but
it has never been verified. Moissan discovered the first and only
known natural Moissanite – in a meteorite.)

A lot is happening in gem-grade diamond synthesis and associated
techniques at the moment. At least two major companies are now
selling Russian-made diamonds in the U.S. in white, blue and yellow
(wholesaling between $3,000 and $5,000 a carat at last Tucson!) and
there’s even a color-change type but I can’t remember who’s producing
it. I can even get colored synthetic diamond rough if anyone wants to
try cutting it.

The same basic technology used to synthesize diamonds is now finding
other uses. GE, in association with diamond house Lazare Kaplan’s
Pegasus Overseas Lt. (POL) subsidiary, is using HTHP (high
temperature/high pressure) to actually whiten rare brown Type IIa
diamonds. Novatek, a company in Provo, Utah, is using the same
general process in its own way to transform some kinds of brownies
(not sure which kind) into saleable yellow-green and green-yellow
stones, and hopes to add pure pinks soon. Unlike GE-POL, it’s working
in association with European Gemological Laboratories so as to share
its discoveries with the gemological community.

In another associated development, a company has just announced a
diamond fracture-filling process that will stand up to torch
temperatures for retipping and other jewelry soldering. There’s lots
of diamond news right now but I don’t want to take up more bandwidth.

Rick Martin

To add to Rick Martin’s excellent post on created diamonds, Chatham
has also jumped into the market with their own created diamonds.
Anyone interested in a “collectors item”? That is how Chatham is
marketing the first one hundred stones. See for yourself at:

The synthetic diamond market seems to be getting somewhat crowded

Charles Heick