Uneven, torn surfaces, (e.g. fractured metals)., Uneven, Gemstones (2009), torn surfaces, (e.g. fractured metals).
Uneven, Uneven, ConchoidalWalter Schumann, Gemstones of the world (2001)
FeO(OH)Arthur Thomas , Gemstones (2009)
Mg 2Al 4Si 5O 18Ulrich Henn and Claudio C.