MN406 Sample ID MN406 • Cabinet F Tourmaline 3.413cm W x 5.979cm H x 3.528cm D • 116g Sample TypeMineralColorBlackLusterVitreous/Silky StreakColorlessCleavage/FractureIndistinct/UnevenSpecific Gravity3.2 Geographic Location/DateMesa Grande CA Mohs Hardness 8 Small opaque black schorl tourmaline. Prismatic and rhombohedral crystals. Small signs of possible feldspar on the top. Description of Mohs scale here