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
{001} Perfect, {110} Distinct, {101} Distinct
Be 4Si 2O 7(OH) 2Anthony et al , Handbook of mineralogy (2001)