Uneven, Uneven, ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle
Conchoidal, ConchoidalArthur Thomas, Gemstones (2009)
Na 2(Ti,Fe)Si 4(O,F) 11Ulrich Henn and Claudio C.
K(Ca,Na) 2Si 4O 10(OH,F) · H 2OMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references