Pyrrhotite
From LoveToKnow 1911
PYRRHOTITE, a mineral species consisting of iron sulphide and crystallizing in the hexagonal system. The formula is Fe n, Sn+, where n may vary from 5 to 16; usually it is Fe, S8 or Fe l s S12, the latter being also the composition of the artificially prepared compound. Small amounts of nickel and cobalt are often present.
Acmite Spodumene Jadeite NaAl (S103)2.
Wollastonite CaS103.
Pectolite HNaCa2(S103) 3.
Rosenbuschite.. Na2Ca3[(Si,Zr,Ti)03]4.
Anorthic Series.
Rhodonite M nS103.
Babingtonite (Ca,Fe,Mn)S103 Fe2"(S103)3.
Hiortdahlite. ... (Ca,Na)2F[(Si,Zr)02].
For details respecting the special characters and modes of occurrence of most of these species reference may be made to the respective headings: others not so treated are briefly mentioned below. Hedenbergite, or calcium iron pyroxene, is a black mineral closely allied to diopside and, owing to the isomorphous replacement of iron by magnesium, there is no sharp line of division between them. Schefferite, or manganese pyroxene, is a brown mineral found in the manganese mines of Sweden. Pectolite is a secondary mineral occurring as white masses with a radially fibrous structure in the veins and cavities of basic igneous rocks. Babingtonite is found as small black crystals on felspar in the granite of Baveno in Italy, and in the Haytor iron mine in Devonshire. Rosenbuschite, hiortdahlite, and some other rare members containing zirconium and fluorine, occur as accessory constituents in the nephelinesyenite of southern Norway.
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