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)
Uneven, Conchoidal to uneven, ConchoidalWalter Schumann
Distinct on {110}, imperfect on {010}, poor on {001}