O

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Okenite                  Ca10Si18O46· 18H2O    Olivina                    (Mg,Fe2+)2SiO4    Orneblenda            (Ca,Na,K)2-3(Mg ,Fe2+, Fe3+,Al)5(Si,Al)2Si6O22(OH,F)2    Osumilite                (K,Na)(Fe2+,Mg)2(Al,Fe3+)3(Si,Al)12O30

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