Jnat ?

[MasterOfPups]

I got this stone off yahoo, it was represented as a Kato era Nakayama. It is very hard and fine, cuts slowly on its own milky colored slurry, but seems to produce a good edge. It was sealed in black paint and the back of it looked suspicious to me, not like any other naturals that I have seen. Kind of a mortar mix look to it.
So, I stripped the paint and this is what was under it. Very even layers of gray. The saw marks actually look more like marks from a grinder.
Anybody ever see a jnat like this ?I am wondering if it is even a natural stone ?

 

[Christian1212]

Looks like a jnat to ne

 

[Legion]

I'm not 100% it is a Jnat, but it could be for sure. I am pretty sure it is natural.

 

[MasterOfPups]

The layering looks weird to me. And the grooves on the back, unless those are the remains of drill holes.

 

[Legion]

The layering looks weird to me. And the grooves on the back, unless those are the remains of drill holes.

The layering is probably just sedimentary layers (think Hindostan). The grooves I'm not sure, but they could be some sort of remnants from when they cut the big block into hone thick slabs.

 

[Steve56]

Looks natural to me, likely a JNat

 

[cotedupy]

The back is a little unusual isn't it, but even still - another vote for jnat here.

The real kicker for me is the size. It would be extremely uncommon to find a non-Japanese stone, that looked like that, cut that wide.

 

[PLANofMAN]

Yes, it's a natural stone, and yes, I've seen similar jnats with chipping like that.
The grooves in the back are likely tool marks left over from splitting the stone when it was quarried.

 

[alx gilmore]

From what ever "era" that stone is from, it does not look like a product that Kato would have released from his shop. The gray, simple, plain unfinished form and presentation allows for the theme that it could have come from any of the mines near Kyoto or Kameoka. I hope it is a good stone for your use.

Alx

 

[MasterOfPups]

It does put an impressive edge on a razor, but requires nagura. Doesn't seem to have a lot of cutting power on its own, but as hard as it is, that isn't surprising.

It is currently lapped on a worn 600 Atoma and looks frosty from the 600 grit scratches. I had previously lapped it to 1200 to get the scratches out, but it took forever to work up a nagura slurry.

 

[musicman980]

It looks like the stone was cut with a small contractor's tile saw, not anything that would have come from one of the more typical jnat mining operations in my opinion. Considering the unusual shape of the bottom too, perhaps this was a piece found outside of a mine that was picked up and cut by a local?