Sub-Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), Brittle
ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009), Uneven
Cu2H2Si2O5(OH)4
(Al,Mg) 8(Al,Si) 6O 20Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references