Originally Posted by
StoneSeeker
i usually put a razor to it at different points of the process and try to find the slot it fits in with the known stones i have. set the bevel with a 1k, then go to the mystery stone. does it improve the edge? if so reset the bevel and go to the 4k and then the mystery stone. when testing the edge you can use the thumb pad test or hanging hair test.
there are also other ways like checking the scratch pattern on steel, or feeling the stone with you fingers or tongue. of course after cleaning the stone.