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
Uneven, ConchoidalWalter Schumann, Conchoidal
None, may show partings on {0001} and {10 1 1}
Fe 2O 3Arthur Thomas , Gemstones (2009)