Uneven, Uneven, ConchoidalArthur Thomas, Gemstones (2009)
Gemstones (2009), UnevenArthur Thomas, Gemstones (2009)
Na 4AlBeSi 4O 12ClMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references
Al 2SiO 5Arthur Thomas , Gemstones (2009)