Thread: Please help me identify this misty hone.

I stumbled on this stone the other day, it was embedded in a wooden box, the glue was probably shellac, I had to disassemble the box to get it out, it was covered with grime and was dished but now it’s nice and clean.
The dishing wasn’t too bad… maybe about 1/16th inch, so at first I thought ...”oh I’ll be done in a few minutes”… after the 8 hours I almost gave up on this cursed thing, but I wasn’t about to let it get the better of me, though I think it may have taken a few days off the rest of my life…

-It is about 8”x2”x1”
-Cream colored and almost yellow when wet.
-It is hard… very hard… probably harder than most barber hones.
-Difficult to produce slurry because it’s so hard, but when it does it is cream or white.
-Puts a fine edge on my razor, a comfortable shave, the scratch pattern looks “hazy” but easily polished on the strop.
-Lots of feedback, you can feel “drag” when honing which gets heavier as the edge sharpens… I would say it’s a pleasure to hone with this… like driving a sports car.

I believe this is a natural hone and I have included photos of the unfinished underside of the hone… maybe this was at one end of the vein.

So here is the question… what manner of beast is this?

BTW… the thread title was supposed to be "... mystery hone", but sadly I am unable to correct.