Somehow a real diamond got mixed up with the fakes. This summer the Gemological Institute of America reported its highest-ever single swoop of synthetic diamonds masquerading as naturals—1,101 artificial stones out of a parcel of 1,102. Efforts to pass off synthetic melee (variously given as under 0.15 or 0.2 carats) have increased exponentially since the GIA offered its detection service in 2016, the organization stated.
But while synthetics have improved substantially in quality, their chief risk to the diamond trade appears to be not false pretenses but positive consumer response. Customers willingly buy the man-made versions, attracted by lower prices as well as claims of ethical superiority that challenge the allure of a naturally created wonder.
And in a high-tech society, the lab-created substitutes can inspire a sense of wonder too. They’re created by one of two methods. Expressed simply, the high-pressure, high-temperature (HPHT) process dissolves graphite or another form of carbon through a metal alloy to bond with tiny seed diamonds and grow atomically into gem-sized diamonds.
In another process, chemical vapor deposition (CVD) precipitates carbon through a mix of hydrogen and methane gases to grow onto the seed diamonds. Colour might appear as the stones grow or might be applied post-growth. The lab rough then undergoes cutting and polishing.
Among the larger faceted synthetics seen so far by the GIA, one came to over five carats from the CVD process. Another weighed over 10 carats, originating from an HPHT rough surpassing 32 carats.
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