Greigite

Greigite

Greigite is an iron sulfide mineral with formula: Fe(II)Fe(III)2S4. It is a magnetic sulfide analogue of the iron oxide magnetite (Fe3O4). Greigite occurs as microscopic (< 0.03 mm) isometric hexoctahedral crystals and as minute sooty masses. It is a bio-mineral produced by and found in magnetotactic bacteria. It is a pale pink to metallic blue-black mineral with a specific gravity of 4.049 and a Mohs hardness of 4 to 4.5.

It was first described in 1964 and named for Penn State mineralogist and physical chemist Joseph W. Greig (1895-1977).

References

* [http://rruff.geo.arizona.edu/doclib/hom/greigite.pdf Mineral Data PDF]
* [http://www.mindat.org/min-1747.html Mindat with location data]
* [http://webmineral.com/data/Greigite.shtml Webmineral data]


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