Anyone familiar with this stone?

[Blackbeard]

Not finding much info on google except a few images, was wondering about the grit #'s (I'm guessing the darker color is lower/coarser)




Was running my hated Kershaw Identity beater knife on it, was able to get it in better shape vs Lansky blade medic, I'm still a noob at sharpening.
Had it slicing paper pretty good, but tried the lighter side and made the blade worse, guess I lost the burr, so went back to the darker side and finished it on a piece of leather, I need more practice.