Uneven, UnevenArthur Thomas, Gemstones (2009)
ConchoidalAnthony et al, Handbook of mineralogy (2001), ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle, Conchoidal
KCa 4Si 8O 20(F,OH) · 8H 2OUlrich Henn and Claudio C.
CaBe 2(PO 4) 2Michael OâDonoghue , Gems, Sixth Edition (2006)