Tenacity
Solubility
Durability
Specific Gravity
Fracture
Cleavage
Mohs Hardness
Chemical Composition
NaCa 2(Mg 4Al)Si 6Al 2O 22(OH) 2Michael OâDonoghue , Gems, Sixth Edition (2006)
Uneven, Subconchoidal, Splintery
Good on {110}, poor on {100}
Al 2SiO 5Michael OâDonoghue , Gems, Sixth edition (2006) More from other references