Greetings everyone,

I went to the flea market today and picked up a black "stone" marked Edison. (It's hard to read in the photos, but it's much clearer in person.) I'm assuming it's a Barber's hone, but it didn't come with a box or anything. Other than rinsing it off, I haven't done anything with it yet, as you can see by the pictures below. I tried searching this forum, the B&B forum, and Google, but I didn't find any info on this hone. Can anyone tell me whether it's a decent one and what grit it might be? I only paid $2 for it, so I don't have much to lose. Thanks.