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Created or synthetic gemstones are made in laboratories not in rocks. They have the same composition and crystal structure as natural gemstones, so their optical and physical properties are almost identical. They can usually be identified by the differences in their inclusions.
Man has tried to reproduce gemstones for thousands of years, but it was not until the late 1880’s that any significant success was achieved. Around 1900 August Verneuil devised a technique to manufacture ruby that is still used today.
The verneuil “flame-fusion” method involves dropping the powdered ingredients into a furnace and melt as they fall through a flame hotter than 2,000C fusing into liquid drops. These drip onto a pedestal and crystallize. As the pedestal is withdrawn, a long, cylindrical crystal, which is known as a boule, forms.
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Other methods such as the flux-melt technique involve melting the powdered ingredients and fusing them in a solvent (flux) in a crucible. The material is then kept at a very high temperature for months before being left to cool very slowly.
Exciting new developments in the science of synthetic gemstones have occurred in the last couple of years. Apollo Diamond Inc. in Massachusetts and Florida-based Gemesis Corp. have each created a new type of lab-made diamond that is extremely difficult, though not impossible, to distinguish from natural diamonds.
The new lab-made diamonds from Apollo Diamond are formed in a few days through a process called chemical vapor deposition. A plasma cloud of carbon is deposited onto diamond wafers and diamond crystal is formed. The wafer “seeds” grow into small diamond bricks - rough diamonds that are sliced into wafer thin slices and cut and polished into diamonds.
At Gemesis, synthetic diamonds are produced through a high-pressure, high-temperature technique that imitates the geologic conditions under which natural diamonds are formed. Graphite, which is a form of carbon, is put in a capsule placed under high temperature and pressure. It breaks down into atoms and moves through a metal solvent to bond to a tiny diamond seed. It crystallizes layer by layer, and three or four days later, the stone that is thus formed is removed from the chamber and cut and polished into a synthetic diamond.
These new lab-made diamonds have created ripples throughout the jewelry industry since they are undetectable to the eye or a jeweler's loupe. The difference can only be detected through the use of sophisticated equipment found in diamond-grading labs. Special devices created to detect synthetics shine a light through a stone to analyze its refractory qualities or use ultraviolet light to reveal the crystal's internal structure.
Both companies have stated that their diamonds will be properly labeled, but the potential for fraud is nonetheless still present. All the diamonds in the Jewelry 21 range are currently natural gems. | |
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