Tenacity
Solubility
Durability
Specific Gravity
Fracture
Cleavage
Mohs Hardness
Chemical Composition
From the Greek, oligos and kasein, little cleavage.
Na(90-70%)Ca(10-30%)(Al,Si)AlSi 2O 8Michael OâDonoghue , Gems, Sixth Edition (2006)
Al 2O 3Ulrich Henn and Claudio C.