A friend in Kalamazoo let me borrow his slip honing stones. In his email he stated that the Reddish brown one is 1000 grit, the white on is 4000 grit and the yellow one is 8000. I can believe the yellow being 8000 because I get very little residue on the razor or the stone itself (using water on all 3), but I am not sure about the other 2.
I started out with the reddish brown and noticed "some" metal grayish residue. Then when I went to the white 4000 grit, and honed I noticed a lot more grayish residue that I occasionally rinsed off, and wiped off the blade.
Could it be that the 1000 and 4000 are backwards, the white one being really 1000 instead of 4000?
I can post pictures if you would like. They are small stones, wedge shaped, being thicker on one length than the other length. About 4" long and about 2" wide. No names or other on them.