Anybody has a MARTTIINI SHARPENING STONE ? Natural or man-made? Grit? Experiences?

[knivve]

Gentlemen!

Anybody knows something about the stone?

The factory says on their website only the followings:

http://www.marttiini.fi/Sharpening-stone

Traditional sharpening stone of the Lappish serizite quartzite.
The sharpening stone has two surfaces of different grit grades: first the blade is sharpened with circular movements on the rougher side, after which the blade edge is finished on the finer side by removing the circular marks. The sharpener also includes a groove for sharpening hooks.

I asked the factory - and some dealers - some questions but they did not answer. So knows anybody something about the stone?

It’s natural stone or man-made?
If natural, is it naturally two sided or glued ? (I know that there are natural two-sided sharpening stones, but hey are very expensive.)
Grit sizes ?

Thank you in advance:
K.

 

[Obsessed with Edges]

I'd assume it's two pieces glued together, of silica-based natural stone. The 'serizite quartzite' references natural stone, apparently from Norway, based on what I'm seeing in web searches. In particular, the 'serizite' (also seeing it spelled as 'sericite') description might be a reference to a type of weathered mica. The 'Traditional sharpening stone' reference would also appear to hint at natural origins for the stone. As with any natural stone, it'd be difficult to pin down what the grit size would be, as all natural stones are variable.


David