Hi another ID where i ask for further help on identification, it seems to be a kind of Schist with a nice pattern quite comparable to the Rouge Du Salm (Special Red BBW Layer) has...
its a very fine finisher in my thinking above 10k but i could not evaluate if this one could be finer...
https://farm3.staticflickr.com/2833/...4bc686_c_d.jpg
https://farm3.staticflickr.com/2833/...4bc686_c_d.jpg
https://farm4.staticflickr.com/3757/...cf282d_c_d.jpg