Conchoidal, Conchoidal, Gemstones of the world (2001)
Uneven, Uneven, Gemstones of the world (2001) More from other references
SiO 2 · nH 2OWalter Schumann , Gemstones of the world (2001)
Ca 10Mg 2Al 4(SiO 4) 5(Si 2O 7) 2(OH) 4Ulrich Henn and Claudio C.