Tenacity
Brittle
-
Solubility
-
-
Durability
-
-
Specific Gravity
3.7-3.83.85-3.94
1
7.18
👆🏻
Fracture
Subconchoidal, Conchoidal
Conchoidal, Uneven
Cleavage
Distinct on {010}
{010} Good, {100} Distinct
Mohs Hardness
7-7.55-5.5
2
10
👆🏻
Chemical Composition
(Fe,Mg,Zn) 2Al 9(Si,Al) 4O 22(OH) 2Ulrich Henn and Claudio C.
(Mn2+ ,Fe2+ ,Mg,Ca) 2(PO 4)(F,OH)Michael OâDonoghue , Gems, Sixth Edition (2006)