Tenacity
Solubility
Durability
Specific Gravity
Fracture
Cleavage
Mohs Hardness
Chemical Composition
ConchoidalWalter Schumann
SiO 2Walter Schumann , Gemstones of the world (2001)
Mg 3Al 8BeO 16Walter Schumann , Gemstones of the world (2001) More from other references