Uneven, Subconchoidal, Uneven, Subconchoidal, Conchoidal, Brittle
Uneven, Uneven, ConchoidalWalter Schumann, Gemstones of the world (2001) More from other references, Conchoidal, Brittle
NaAlSi 2O 6 · H 2OMichael OâDonoghue , Gems, Sixth edition (2006) More from other references
Fe 2O 3Arthur Thomas , Gemstones (2009)