Conchoidal, Brittle, Conchoidal, Brittle, Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), Brittle, Conchoidal
Conchoidal, UnevenArthur Thomas, Gemstones (2009), Brittle
Fe 3Al 2(SiO 4) 3Arthur Thomas , Gemstones (2009)
Zn 2(AsO 4)(OH) · H 2OMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references