Tenacity
Brittle
Brittle
Solubility
-
Soluble
Durability
-
-
Specific Gravity
1.793.30-3.50
1
7.18
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Fracture
Irregular/uneven
Uneven, ConchoidalWalter Schumann, Conchoidal
Cleavage
Perfect on {10bar10}
Perfect on {110}, poor on {101}, {001} rare
Mohs Hardness
2.55
2
10
👆🏻
Chemical Composition
Ca6(Al,Si)2(SO4)2B(OH)4(OH,O)12•26(H2O)
Zn 4Si 2O 7(OH) 2H 2OMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references