Gemstone Type : Natural African Tanzanite Naturally Included Approx. Weight (ct) : 0.15 Cts. Shape : Oval Cut Size/Dimension : 4 x 3 MM Depth : 1.5 MM Color : Lavender Blue Clarity : Transparent Luster : Good Origin : Africa Hardness : 6.5 - 7 Specific Gravity : 1.68 - 1.72 Refractive Index : 1.68 - 1.72 Chemical Composition : Ca2Al3(Si04)3(OH), Treatment : Natural