Tenacity
Solubility
Durability
Specific Gravity
Fracture
Cleavage
Mohs Hardness
Chemical Composition
{001} Perfect, {110} Distinct, {101} Distinct
Be 4Si 2O 7(OH) 2Anthony et al , Handbook of mineralogy (2001)
{010} Good, {100} Distinct
(Mn2+ ,Fe2+ ,Mg,Ca) 2(PO 4)(F,OH)Michael OâDonoghue , Gems, Sixth Edition (2006)