I can't. As mentioned above, you have to have the stone in hand to be able to say anything about it.
Now do people guess? Well of course they do, that's what the whole bidding on stones at the Japanese auctions is based on. You learn to identify looks and patterns and bid and if you are successful the stones performs as you would expect. That approach is risky but fun if you are ok with the risk.
So you have 2 options. One you evaluate the stone yourself, two you send it out to somebody to do it for you.
Can you post your own pics of this stone? Dry and wet. Just curious.
The stone is at my apartment and I moved to another country to work there for God knows how long and I might return around Christmas, but by then I might forget about the stone and everything.
The thing is that for whatever reason he wants that stone badly. He hinted a few months ago when I send him the stone to look at it that he's looking for exactly like that one. Then, he contacted me a a few weeks later saying if I'm intrested and I said something like - ''I'm still new and I'm not sure what to do with it, but I'm going to keep it for now''. And a few days ago he called me and it sounded like he wanted really bad. How could a Jnat with 3-3.5 hardness be so important for him, since he has at least 4 or 5 other Jnats and God knows how many others like coticules, thuringians and what not?
For someone like him who's very knowledgeable as well as owning countless stones and razors and having connections finding such or even better stone should not be a problem.