Uneven, torn surfaces, (e.g. fractured metals)., Uneven, Gemstones (2009), torn surfaces, (e.g. fractured metals).
ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
FeO(OH)Arthur Thomas , Gemstones (2009)
SiO 2Ulrich Henn and Claudio C.