Tenacity
Brittle
-
Solubility
Soluble
-
Durability
-
-
Specific Gravity
3.30-3.503.355-3.433
1
7.18
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Fracture
Uneven, ConchoidalWalter Schumann, Conchoidal
Uneven
Cleavage
Perfect on {110}, poor on {101}, {001} rare
{???} Good, {???} Good
Mohs Hardness
5-9999
2
10
👆🏻
Chemical Composition
Zn 4Si 2O 7(OH) 2H 2OMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references
(Ca,Mn2+ ,Fe2+ ) 3Al 2BSi 4O 15(OH)Anthony et al , Handbook of mineralogy (2001)