Chemical Composition :
Silicon Carbide – SiC
Classification / Type :
This is a man made material. The term synthetic is used since it has a natural counterpart as inclusions seen in diamonds and other gemstones.
Crystal System / Forms :
Cuts & Uses :
0.105 (high fire)
Strong doubling of facet edges, inclusions and culet (generally seen through kite facet), reflective needles.
Optic Character :
Anisotropic, D.R.; Uniaxial Positive
Refractive Index / Birefringence :
2.648 – 2.691 / 0.043
Simulants (with separation tests) :
G.G.G. (dispersion, doubling, S.G.), Y.A.G. (dispersion, doubling, S.G.), Synthetic Cubic Zirconia (S.G., dispersion, doubling), Diamond (dispersion, doubling, inclusions, S.G.), Strontium Titanate (dispersion, doubling, S.G.), Sphene (dispersion, inclusions), Synthetic Rutile (S.G., dispersion), etc.
Specific Tests :
Moissanite probes are available which are defined for synthetic moissanite values of thermal conduction such as moissanite thermal probe.
Large crystals are grown by sublimation from a feed powder, diffusion through graphite and growth directly from the vapor phase on a seed crystal. In the sublimation process, the silicon carbide vaporizes and recrystallises without passing through the liquid stage.