Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009), Brittle, Conchoidal
Brittle, UnevenArthur Thomas, Gemstones (2009), Brittle, Uneven
CaCO 3Ulrich Henn and Claudio C.
(Mg,Fe)Al 3(BO 4)(SiO 4)OUlrich Henn and Claudio C.