Conchoidal, Uneven, ConchoidalArthur Thomas, Brittle
Gemstones (2009), UnevenArthur Thomas, Gemstones (2009), Brittle, Uneven
Ag 3SbS 3Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
ThCa 2Si 8O 20Walter Schumann , Gemstones of the world (2001) More from other references