Irregular/uneven, UnevenArthur Thomas, Gemstones (2009)
Uneven, Uneven, ConchoidalArthur Thomas, Gemstones (2009)
CaAl 2Si 4O 12 -6H 2OArthur Thomas , Gemstones (2009)
Na 4AlBeSi 4O 12ClMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references