1 Physical Properties
1.1 Tenacity
1.2 Solubility
Gelatinises in acids
Insoluble in acids
1.3 Durability
Not Available
Not Available
1.4 Specific Gravity
1.5 Fracture
Uneven, Conchoidal, Brittle
Uneven, ConchoidalArthur Thomas, Gemstones (2009)
1.6 Cleavage
Distinct on {110}
{110} good, 100 moderate, parting on {092} and {011}
1.7 Mohs Hardness
1.8 Chemical Composition
(Na,Ca)4-8Al6Si6(O,S)24(SO4,Cl)1-2
TiO 2Michael OâDonoghue , Gems, Sixth Edition (2006)