Name of mineral :corundum Mohs hardness :9 Refractive index :1.762~1.770 Specific gravity :4.00 Weight : 4.31 ct Size (mm) : L 9.2×W 7.9×D 6.20 sri lanka, untreated Gem quality us $25,000 宝石辞典もくじ 戻る 次ページ