Tenacity
Solubility
Durability
Specific Gravity
Fracture
Cleavage
Mohs Hardness
Chemical Composition
(Ca,Cr)MgSi 2O 6Gemdat.org , Management Team (2012)
From the Greek, oligos and kasein, little cleavage.
Na(90-70%)Ca(10-30%)(Al,Si)AlSi 2O 8Michael OâDonoghue , Gems, Sixth Edition (2006)