Conchoidal, Brittle, Conchoidal, Brittle, Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), Brittle, Conchoidal
Conchoidal, Conchoidal, Gemstones of the world (2001) More from other references, Conchoidal, Brittle
[001] good, [210] distinct
111 (perfect in four directions)