USA, Southern and central Africa, green, blue, China, India, USA, Italy, green, blue, China, India, USA, Italy
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H 4Mg 3Si 2O 9Walter Schumann , Gemstones of the world (2001) More from other references
NaFe 3+ 3 Al 6 (BO 3 ) 3 Si 6 O 18 (O,F,OH) 4 Anthony et al, Handbook of mineralogy (2001)