Tenacity
Brittle
-
Solubility
Gelatinises in acids
-
Durability
-
-
Specific Gravity
2.4-2.53.07-3.13
1
7.18
👆🏻
Fracture
Uneven, Conchoidal
Conchoidal, Uneven
Cleavage
Distinct on {110}
{100} Perfect, {010} Distinct, {102} Distinct
Mohs Hardness
5-63-3.5
2
10
👆🏻
Chemical Composition
(Na,Ca)4-8Al6Si6(O,S)24(SO4,Cl)1-2
Zn 2(Fe2+ ,Mn2+ )(PO 4) 2 · 4H 2OMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references