UnevenArthur Thomas, Gemstones (2009), UnevenArthur Thomas, Gemstones (2009), Conchoidal, Brittle
Uneven, UnevenArthur Thomas, Gemstones (2009)
Ca 2Mg 5Si 8O 22(OH) 2Ulrich Henn and Claudio C.
Pb 26Ag 10Cu 24Cl 62(OH) 48 · 3H 2OWalter Schumann , Gemstones of the world (2001) More from other references