Tenacity
Solubility
Durability
Specific Gravity
Fracture
Cleavage
Mohs Hardness
Chemical Composition
Subconchoidal, Uneven, Conchoidal
Mn2+ Al(PO 4)(OH) 2H 2OMichael OâDonoghue , Gems, Sixth Edition (2006)
Conchoidal, ConchoidalWalter Schumann
Perfect in three directions
CuSiO 2(OH) 2Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references