Tenacity
Solubility
Durability
Specific Gravity
Fracture
Cleavage
Mohs Hardness
Chemical Composition
{110} Perfect, {110} Perfect, {110} Perfect
(Zn,Fe)SMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references
ConchoidalWalter Schumann
Perfect on {010}, good on {100}
Be 2BO 3(OH)Ulrich Henn and Claudio C.