Originally Posted by
gugi
It means that when the quartz or whatever is the cutting media in that rock crystalized, the sizes are all kinds and nobody sorted them out selecting only the 12000 grit ones. Same is true for every other natural hone, the range of sizes is much larger than any industrial standard.
I would rate them as slow cutting hones, some of them being significantly better than others in producing a sharp edge on a straight razor.
The grits in there are anything from about 1000 to 100,000.
How it behaves depends on how much of the big ones and how much of the small ones ended up in the particular piece of rock that you bought.