Uneven, UnevenArthur Thomas, Gemstones (2009)
Uneven, Uneven, ConchoidalWalter Schumann, Gemstones of the world (2001) More from other references, Conchoidal, Brittle
Mg 3Si 4O 10(OH) 2Ulrich Henn and Claudio C.
Fe 2O 3Arthur Thomas , Gemstones (2009)