Inesite Structure

Steven Dutch, Professor Emeritus, Natural and Applied Sciences, University of Wisconsin - Green Bay


Inesite Ca2Mn7Si10O28(OH)2•5(H2O) isn't named after a flamenco dancer, or indeed after a person at all. It comes from the Greek word for "fiber," the same root used in "inosilicate."  The silica chains are kinked 5-period double chains.

Above and below the silica chains are strips of manganese octahedra (yellow) and calcium octahedra (green)

The complete structure is shown below. A plan view is at top and an end-on view at bottom.

Hmm. Something about this looks awfully familiar. 5-period kinked silica chains. Strips of manganese octahedra with just enough calcium to require distorted silica chains. Looks an awful lot like rhodonite.

 

Rhodonite tructure viewed end-on, above.

Pull the strips apart.

Now move the strips vertically and join the silica chains. And you have the inesite structure. The tunnels created provide space for water molecules

A plan view. Pull the strips in rhodonite apart.

And join the silica chains (lighter strips are further from the viewpoint). This isn't exactly a polymorph of rhodonite because of the additional water. Although no such mineral is listed, it's a good bet there's an analog of inesite that modifies the pyroxmangite structure.


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Created 22 April 2013, Last Update