Tenacity
Solubility
Durability
Specific Gravity
Fracture
Cleavage
Mohs Hardness
Chemical Composition
From the Greek for luster, for its pearly luster on the cleavage.
Al 2(PO 4)(OH) 3Michael OâDonoghue , Gems, Sixth Edition (2006)
Ca 2B 5SiO 9(OH) 5Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references