Black Spinel

Chemical Formula: MgAl2O4
Refractive Index:1.712-1.736
Hardness：8 Mohs
Melting Point：1800℃,heat and wax casting
Orignal:Thailand

Spinel is a hard vitreous magnesium aluminum oxide that has been used as a gemstone for centuries.
It can be high temperature for heating and wax casting in Jewelry .Regarding to spinel electroplate ,
the equipment and technique has to be very professional and advanced .Otherwise after wax casting ,
some combustion residue will stick or cover the metal on the stone surface and facets .