Tenacity
Solubility
Durability
Specific Gravity
Fracture
Cleavage
Mohs Hardness
Chemical Composition
Vitreous, pearly on cleavage
(Fe2+ ,Mg,Mn2+ ) 3(PO 4) 2 · 4H 2OMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references
Good on {110}, (110) ^ (1 1 0) ≈87°; parting on {100}
(Na,Fe,Ca)Si 2O 6Ulrich Henn and Claudio C.