Merrihueite, A New Alkali-Ferromagnesian Silicate from the Mezö-Madaras Chondrite

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Science  27 Aug 1965:
Vol. 149, Issue 3687, pp. 972-974
DOI: 10.1126/science.149.3687.972


Merrihueite, a new mineral with the approximate chemical composition (K,Na)2(Fe,Mg)5Si12O30, occurs with iron-rich olivine, iron-poor pyroxene, and nickel-iron in a few chondrules of the Mezö-Madaras chondrite. The refractive index lies between 1.559 and 1.592; the birefringence for each composition is low to moderate. X-ray powder data for merrihueite are nearly identical to those for osumilite, (K,Na,Ca)(Mg,Fe)2(Al,Fe)3(Si,Al)12O30-H2O, and very similar to those for synthetic K2Mg5 Si12 O30. Merrihueite is interpreted as an alkali-ferromagnesian silicate mineral of the osumilite type. It is named in honor of the late Craig M. Merrihue, meteoriticist, of the Smithsonian Astrophysical Observatory.