ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009), Brittle, Conchoidal
Uneven, Brittle, Metallic, Gemstones (2009)
ZrO 2Arthur Thomas , Gemstones (2009)
Na 2[Al 2Si 3O 10] · 2H 2OMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references