Tenacity
Solubility
Durability
Specific Gravity
Fracture
Cleavage
Mohs Hardness
Chemical Composition
{110} Perfect, {110} Perfect
(Fe,Mn) 7Si 7O 21Ulrich Henn and Claudio C.
Uneven, ConchoidalWalter Schumann, Conchoidal
Perfect on {110}, poor on {101}, {001} rare
Zn 4Si 2O 7(OH) 2H 2OMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references