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Conchoidal, Uneven, ConchoidalArthur Thomas, Gemstones (2009), Brittle, Metallic
Mn2+9(SiO 4) 4(OH,F) 2Anthony et al , Handbook of mineralogy (2001)
CaBSiO 4(OH)Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references