Uneven, Subconchoidal, Uneven, Subconchoidal, Conchoidal, Brittle
Gemstones (2009), UnevenArthur Thomas, Gemstones (2009)
NaAlSi 2O 6 · H 2OMichael OâDonoghue , Gems, Sixth edition (2006) More from other references
Al 2SiO 5Arthur Thomas , Gemstones (2009)