Subconchoidal, ConchoidalArthur Thomas, Gemstones (2009), Conchoidal, Brittle
UnevenAnthony et al, Handbook of mineralogy (2001), UnevenAnthony et al, Handbook of mineralogy (2001), Uneven
(Fe,Mg,Zn) 2Al 9(Si,Al) 4O 22(OH) 2Ulrich Henn and Claudio C.
Fe3+ PO 4 · 2H 2OAnthony et al , Handbook of Mineralogy (2001)