Tenacity
Solubility
Durability
Specific Gravity
Fracture
Cleavage
Mohs Hardness
Chemical Composition
(Mg,Fe,Zn)Al 6BeO 12Ulrich Henn and Claudio C.
Conchoidal, ConchoidalWalter Schumann
Perfect in three directions
CuSiO 2(OH) 2Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references