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Moissanite or Diamond?
Moissanite or Diamond?

Moissanite can be used as an imitation diamond. It is the name given to gem-like silicon carbide.

Naturally occurring Moissanite was discovered in 1905 by Dr. Ferdinand Henri Moissan, although synthetic silicon carbide had been produced since 1892 by Eugene G. Acheson who called his new material carborundum, the name being an amalgam of carbon and corundum.
The discovery was in a meteorite in Arizona, and was at first disputed, as it could have been contamination from the carborundum impregnated drill bits which were already in use. Moissanite also oocurs naturally in kimberlite and corundum deposits, albeit in microscopic crystals.
Interestingly, Moissan also predicted in 1892, that diamond could be formed by crystallisation of carbon from iron, a process which is now used in the HTHP High Temperature High Pressure process now used to create synthetic diamonds. In Moissan's time, the high pressures needed could not be achieved.

Gem Moissanite
Charles and Colvard introduced gem quality moissanite into the commercial market, where it created some confusion and excitement because although it is quite easy to differentiate from diamond, many jewellers used to rely on thermal conductivity probes to distinguish diamond from imitations, and as moissanite had a high coefficient of thermal conductivity, it used to give false positives for diamond. Other simple optical checks, such as noticing its strong birefringence (double refraction) are an easy way to distinguish it.

Technical Information
Chemical Composition and NameSiC - Silicon Carbide
Refractive Index2.65 to 2.69
Specific Gravity3.33
Crystalline SystemHexagonal
Dispersion0.104 the Lowest Possible Price

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