Tenacity
Not Available
Not Available
Solubility
Not Available
Insoluble in acids
Durability
Not Available
Not Available
Specific Gravity
2.55-2.65
4.20-4.30
Fracture
Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), Conchoidal, Brittle, Conchoidal, Brittle
Uneven, ConchoidalArthur Thomas, Gemstones (2009)
Cleavage
Perfect {10 1 0}
{110} good, 100 moderate, parting on {092} and {011}
Mohs Hardness
5.5-6
6-6.5
Chemical Composition
(Na,Ca,K) 8(Si,Al) 12O 24(SO 4,Cl,CO 3) 3(H 2O)Arthur Thomas , Gemstones (2009)
TiO 2Michael OâDonoghue , Gems, Sixth Edition (2006)