Hey fellas, I just inherited this combo stone. One of my great grandfathers was a barber, and the other a butcher-- I'm not sure which one it belonged to. The problem is that the grits are not marked anywhere on it. I want to learn how to hone, and need to know where I stand. The dimensions are 6" X 2" X 1", and the light gray side seems to be the finer grit of the two. I'm just hoping for the off chance that somebody out there has seen this stone before, or maybe if anybody has some tips for a newb on determining the grits on this stone? Thanks a lot.