Not a chance. Especially since with Japanese naturals, since they don't really fir the frit rating system.

The only way to figure it out is to try and see how it reacts. And even that will only give you an idea. If you really want to know, the only way is to send it to an expert like So Yamashita for appraisal. He or his father will probably be able to say what it is, where it comes from and when it was mined.

Of course, So is already overworked so that is probably not a realistic option. and it doesn't really matter from a practical perspective.
Give it a try and see where it will fit in your honing setup.