UnevenArthur Thomas, Gemstones (2009), UnevenArthur Thomas, Gemstones (2009)
Conchoidal, Brittle, Conchoidal, UnevenArthur Thomas, Gemstones (2009), Brittle, Conchoidal
Ca 2Mg 5Si 8O 22(OH) 2Ulrich Henn and Claudio C.
CaSO 4Michael OâDonoghue , Gems, Sixth edition (2006) More from other references