Tenacity
Solubility
Durability
Specific Gravity
Fracture
Cleavage
Mohs Hardness
Chemical Composition
ConchoidalWalter Schumann
Perfect on {010}, good on {100}
Be 2BO 3(OH)Ulrich Henn and Claudio C.
{001} Perfect, {010} Good
KAlSi 3O 8Michael OâDonoghue , Gems, Sixth Edition (2006)