UnevenArthur Thomas, Gemstones (2009) Tough, UnevenArthur Thomas, Gemstones (2009) Tough, Brittle, Uneven
Brittle, Metallic, Brittle, Metallic
Mn 8Si 6O 15(OH,Cl) 10Ulrich Henn and Claudio C.
CaZnSiO 4 · H 2OAnthony et al , Handbook of mineralogy (2001)