Tenacity
Solubility
Durability
Specific Gravity
Fracture
Cleavage
Mohs Hardness
Chemical Composition
[010] Perfect, [100] Distinct, [011] Distinct
Amethyst, Clear Quartz, Smoky Quartz, Cacoxenite, Rutile, Geothite, Lepidocrocite
ConchoidalWalter Schumann
Perfect on {010}, good on {100}
Be 2BO 3(OH)Ulrich Henn and Claudio C.