Tenacity
Solubility
Durability
Specific Gravity
Fracture
Cleavage
Mohs Hardness
Chemical Composition
Perfect on [001], good on [010], imperfect on [110]
Ca(70-90%)Na(30-10%)(Al,Si)AlSi 2O 8Michael OâDonoghue , Gems, Sixth Edition (2006)
From the Greek for luster, for its pearly luster on the cleavage.
Al 2(PO 4)(OH) 3Michael OâDonoghue , Gems, Sixth Edition (2006)