Gems, Sixth Edition (2006)
UnevenAnthony et al, Handbook of mineralogy (2001) More from other references, UnevenAnthony et al, Handbook of mineralogy (2001) More from other references, Brittle, Metallic
Quartz: SiO2 Rutile: TiO2
CoAsSAnthony et al , Handbook of mineralogy (2001)