Sub-Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), Brittle
UnevenArthur Thomas, Gemstones (2009), UnevenArthur Thomas, Gemstones (2009)
Cu2H2Si2O5(OH)4
Ca 2(Mg,Al) 6(Si,Al,B) 6O 20Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references