1 Physical Properties
1.1 Tenacity
1.2 Solubility
Gelatinises in acids
Partly soluble in HCl.
1.3 Durability
Not Available
Not Available
1.4 Specific Gravity
1.5 Fracture
Uneven, Conchoidal, Brittle
ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
1.6 Cleavage
Distinct on {110}
{100} perfect; {110} and {1 1 0} good; {010} poor
1.7 Mohs Hardness
1.8 Chemical Composition
(Na,Ca)4-8Al6Si6(O,S)24(SO4,Cl)1-2
(Ca,Mn2+ )Si 3O 9Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references