Gemstones (2009)
Conchoidal, Brittle, Conchoidal, Brittle, Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), Brittle, Conchoidal
Al 2SiO 5Arthur Thomas , Gemstones (2009) More from other references
Fe 3Al 2(SiO 4) 3Arthur Thomas , Gemstones (2009)