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
{100} Perfect, {001} Perfect
Na(Mn2+ ,Ca) 2Si 3O 8(OH)Michael OâDonoghue , Gems, Sixth Edition (2006)