ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009), Brittle, Conchoidal
Uneven, UnevenArthur Thomas, Gemstones (2009)
ZrO 2Arthur Thomas , Gemstones (2009)
Cu 5(SiO 3) 4(OH) 2Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references