Handbook of mineralogy (2001), Difficult, Fibrous
UnevenAnthony et al, Handbook of mineralogy (2001) More from other references, UnevenAnthony et al, Handbook of mineralogy (2001) More from other references, Brittle, Metallic
Ca 6Si 6O 17(OH) 2Michael OâDonoghue , Gems, Sixth Edition (2006)
CoAsSAnthony et al , Handbook of mineralogy (2001)