Tenacity
Solubility
Durability
Specific Gravity
Fracture
Cleavage
Mohs Hardness
Chemical Composition
On {10 1 0}, perfect; parting on {000 1 }
(Zn,Mn2+ )OMichael OâDonoghue , Gems, Sixth Edition (2006)
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)