Gemstone Type : Natural Black Golden Star Sapphire 6 Rays Approx. Weight (ct) : 1.35 Cts. Shape : Oval Cabochan Size/Dimension : 8 x 6 MM Depth : 3 MM Color : Black Golden Clarity : Opaque Luster : Good Origin : Thailand Hardness : 9 Specific Gravity : 3.9 - 4.1 Refractive Index : 1.76 - 1.78 Chemical Composition : Al2O3 Treatment : Natural