Uneven, Conchoidal, UnevenArthur Thomas, Brittle
Subconchoidal, Conchoidal, Brittle, ConchoidalArthur Thomas, Gemstones (2009)
Fe2+ CO 3Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
TiO 2Michael OâDonoghue , Gems, Sixth edition (2006) More from other references