Tenacity
Solubility
Durability
Specific Gravity
Fracture
Cleavage
Mohs Hardness
Chemical Composition
Fair in four directions forming octahedrons
Cu 2OMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references
(Ca,Fe,Mn,Mg) 3Al 2BSi 4O 15(OH)Walter Schumann , Gemstones of the world (2001) More from other references