4.85 Cts. Natural Flawless Sky Blue Briolette Topaz, Size/Dimension : 13 x 7.5 MM Depth : 7.5 MM , Clarity : Transparent, Luster : Good Origin Brazil, Hardness : 8 Specific Gravity : 3.4 - 3.5+ Refractive Index : 1.61 - 1.64 Chemical Composition : Al2(OH,F)2SiO4 Treatment : Natural