ConchoidalArthur Thomas, Gemstones (2009)
Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009), Brittle, Conchoidal
Tourmaline is a series of several different minerals with unique chemical formulas.
CaCO 3Ulrich Henn and Claudio C.