Tenacity
Solubility
Durability
Specific Gravity
Fracture
Cleavage
Mohs Hardness
Chemical Composition
(Na,Ca,K) 8(Si,Al) 12O 24(SO 4,Cl,CO 3) 3(H 2O)Arthur Thomas , Gemstones (2009)
{110} Perfect, {110} Perfect, {110} Perfect
(Zn,Fe)SMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references