Marcassite
The marcassite is a Sulfure of Fer running in the Nature. It is the polymorphic orthorhombic, of the Pyrite. Of formula FeS2 , it belongs to the Groupe of space Pnnm . The S2 group forms a stacking ideally hexagonal in the marcassite, cubic in the Pyrite. The provision of the Iron in the octahedral ones formed by the Sulfur, as well as the deformation of these octahedral, reduced Symmetry with orthorhombic. The structure of the marcassite is connected to that of the Pyrrhotite as the structure of the Pyrite is connected to that of the Galène.
Of Color slightly clearer than that of the Pyrite, normally the marcassite gives microcrystalline masses. It is formed in the Zone of reduction, starting from acid solutions containing of the ions Fer and Sulfure.
The marcassite can be also formed by hydrothermal deposit basic temperature. It is a common mineral though much less than the pyrite, but it does not have any economic importance.
History
The marcassite is already known with the Préhistoire to make fire. Our ancestors struck a glare of Silex on a ball of marcassite, split by the medium and posed near a mushroom (the Amadou).
Layers
The marcassite is a Minerai enough running. One finds large Gisement S of marcassite in France, for example in the Pays of Othe
See too
External bonds
- Marcassite, page of the site cybernat, University of Le Havre
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