If you ask in the paint shop for the powder they use to make pea green colored paint, the color comes from Chromium oxide. Cr Ox. This powder if you sprinkle it on a piece of smooth leather is about the finest synthetic hone available.

First, see if you can find the powder pigment that they use to make green paint.
Second, the hone you have found would be just great as long as you have the CR OX covered leather hone to finish with.

Hope this helps.

One more thing. In Croatia, your older men, your Grandads etc., must have used something to shave when they were young. ASK AND THEY MAY WELL TELL ABOUT SECRET CROATIAN THINGS THAT ARE BETTER THAN ANYTHING WE CAN TELL YOU ABOUT. Honest, the old guys are a real source of information and what they know is worth finding out about. When you know, tell us ,because we are all still looking for perfection.

Good local hunting.