What is this slate-like rock?

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Offline Tom86

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What is this slate-like rock?
« on: 29/09/2015 12:51:25 »
Hi everyone,

I've recently returned from a holiday in Mauritius where I found this piece of what I think is slate while walking along the beach on the south west coast.

It has a very shiny, almost a silvery metallic surface which I've not seen on a slate before, and I have not been able to find anything similar while searching on google.

I thought it was man-made at first, but you can see the same metallic colour on all the layers so I guess it must be natural. Someone has suggested that it could be Mica.

Photos:













Hopefully the photos are ok, it is quite difficult to capture the metallic look of it.
« Last Edit: 03/10/2015 07:54:08 by chris »

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Offline Bill S

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Re: ID for this slate like rock
« Reply #1 on: 02/10/2015 22:14:43 »
Just from the pics, I would say its a Mica Schist.

The silvery flakes are almost certainly Muscovite Mica.  The darker flecks may be Biotite Mica.  If the colours are true, there is greenish mineral that could be chlorite.

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Offline Bass

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Re: ID for this slate like rock
« Reply #2 on: 03/10/2015 02:28:19 »
BillS has it right. somewhere between phyllite and schist (the difference being that the mica flakes are larger in schist).
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