Anybody has a Marttini sharpening stone ? Natural or man-made? Grit? Experiences?

Gentlemen!

Anybody knows something about the stone?

The factory says on their website only the followings: (link)

Sharpening stone - Marttiini


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 a natural stone or man-made?
If natural, is it naturally two sided or glued ?
Grit sizes (about) ?

Thank you in advance:
K.

At that price I would say what ever method was cheapest to make it. Looks like it might be okay for knives and fish hooks but........

As 10Pups says, probably good for knives and fish hooks. If it is of any use on razors (and that is a really, really big, fat I F) I doubt it would be provide you with an edge even remotely towards one you would want to shave with i.e. low grit, probably. But then again, I really have no idea what I'm talking about as I have never seen or heard of this particular stone.

The only thing I can say for sure is that it is a natural.