Tenacity
Solubility
Durability
Specific Gravity
Fracture
Cleavage
Mohs Hardness
Chemical Composition
70% SiO2, Al2O3, Na2O, K2O
Subconchoidal, Conchoidal
Distinct on {010}, imperfect {110} and {011}
CaCO 3Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references