Hi folks. The stone is a washita in my experience. Very common over here in the UK at one time (and still very popular with woodworkers using naturals) I've a badly dished one I gave up trying to lap. Hard mo'fo's for sure. There is a guy over here who used to sell a lot of Charnleys and he rated the Washita. Mind you, here was a woodworker back in the day. I guess if you could get one really lapped off (must say, the OP's looks like it's on the way) they would have to be worth giving a go as a comparison to more usual finishers. I'd try and get it lapped up to at least 1k if time and patience permits bigG. Hone using a very light oil such as sewing machine oil, or as a more friendly alternative,a soapand water solution. (apologies if you already knew that last bit).