Conchoidal, Conchoidal, Gemstones of the world (2001) More from other references
UnevenArthur Thomas, Gemstones (2009), UnevenArthur Thomas, Gemstones (2009), Conchoidal, Brittle
SiO 2 · nH 2OGemdat.org , Management Team (2012)
Ca 2Mg 5Si 8O 22(OH) 2Ulrich Henn and Claudio C.