Tenacity
Solubility
Durability
Specific Gravity
Fracture
Cleavage
Mohs Hardness
Chemical Composition
Mn2+5(PO 4) 2(PO 3OH) 2 · 4H 2O)Michael OâDonoghue , Gems, Sixth Edition (2006)
{110} Perfect, {110} Perfect
(Fe,Mn) 7Si 7O 21Ulrich Henn and Claudio C.