Splintery, UnevenArthur Thomas, Difficult, Fibrous
UnevenArthur Thomas, Gemstones (2009), UnevenArthur Thomas, Gemstones (2009), Brittle, Metallic
NaAlSi 2O 6Ulrich Henn and Claudio C.
Mn2+ Zn 2SiO 4(OH) 2Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references