Species ........................................................................ Natural Corundum Variety ................................................................................ Green Sapphire DESCRIPTION Shape & Cutting Style ............................................... Pear, Mixed Cut Measurements ................................................. 7.69 x 7.13 x 3.15 mm Carat Weight ............................................................................. 1.35 Carat Color ....................................................................................................... Green Transparency ......................................................................... Transparent Indications of heating present. Chemical Composition ................................................................. Al2O3 Crystal System .......................................................................... Trigonal Mohs Hardness ................................................................................... 9.0 Specific Gravity ..................................................... 3.97 - 4.10 g/cm3 Optical Character .................................................................... Uniaxial Refractive Index ............................................................ 1.757 - 1.779 Birefringence ................................................................... 0.008 - 0.009