Tenacity
Solubility
Durability
Specific Gravity
Fracture
Cleavage
Mohs Hardness
Chemical Composition
(Al,Mg) 8(Al,Si) 6O 20Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
Uneven, Irregular, Conchoidal
Na(Mg 3)Al 6(Si 6O 18)(BO 3) 3(OH) 3(OH)Gemdat.org , Management Team (2012)