Although GE, Sumitomo, and De Beers led the gem diamond growth for decades, the belt apparatus equipment they used was
oversized. Due to the presence of a large temperature gradient, multiple diamond growth in belt apparatuses was not successful.
Russians, on the other hand, began to develop a washer sized ultrahigh pressure technology using split sphere technology. In 1995, retired Korean war general Carter Clarke visited Leningrad and saw how such equipment operated. He ordered three machines with $170,000 and shipped them to University of m
Figure 11.7. The Sumitomo diamonds (left) and De Beers diamonds (center and right).
Florida in Sarasota. These machines were redesigned with computer control of pressure and temperature profiles. In 2005, Clarke formed Gemesis with 23 equipment that were capable to produce about 200 crystals per month (Fig. 11.9).
Gemesis began to sell the polished gems under the trade name of Cultured Diamond. The diamonds were in rich yellow color due to the presence of ample nitrogen impurities. Gemesis priced the yellow diamond at about $4000 per carat that was about 1/3 of natural gem of the same size.
In 1999, Chatham Created Gems of San Francisco displayed Russian diamonds at the world expo of gems in Las Vagas that made the world know about Russians' coming (Figs. 11.10 and 11.11).
Both Gemesis and Russians are increasing their production capacity in Sarasota and in St. Petersburg, respectively. It is estimated that the market is now taking in at least 1000 synthetic diamond gems per month (Fig. 11.12).
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