Tenacity
Solubility
Durability
Specific Gravity
Fracture
Cleavage
Mohs Hardness
Chemical Composition
(Mg,Fe2+ ) 7(SiO 4) 3(F,OH) 2Anthony et al , Handbook of mineralogy (2001)
[010] Perfect, [100] Distinct, [011] Distinct
Amethyst, Clear Quartz, Smoky Quartz, Cacoxenite, Rutile, Geothite, Lepidocrocite