12th Annual Smithsonian.com Photo Contest
Crystallites of pyrite in clayey limestone
Pyrite crystallites formed by bacterial activity inside cocoon-like structures. The bacteria are iron-eating types feeding on iron removed from clayey minerals in limestone. The limestone is a construction stone and the pyrite (an iron sulphide also referred to as Fool's Gold) forms a patina surface which is most damaging to buildings. The scale (lower right) represent 10 microns. A micron is a thousandth of a millimeter.
© Aryeh Shimron.
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||Nov. 28, 2014, 12:45 p.m.