Tenacity
-
-
Solubility
-
-
Durability
-
-
Specific Gravity
3.1-3.52.9
1
7.18
👆🏻
Fracture
Granular
Conchoidal
Cleavage
None
{???} Indistinct
Mohs Hardness
5-64.5
2
10
👆🏻
Chemical Composition
Ca 2(Mg,Fe)Al 2(SiO 4)(Si 2O 7)(OH) 2 · H 2O)Arthur Thomas , Gemstones (2009)
(Zn,Cu)Al 6(PO 4) 4(OH) 8 · 4H 2OMichael OâDonoghue , Gems, Sixth Edition (2006)