Unknown light gray sharpening stone

[Andrew Pitonyak]

I borrowed the stone and will probably have it for only another day. The question is, what is it?

Hopefully, I will be able to post some photos from my phone since I'm traveling and do not have access to computer.

The coloring is a light gray. When I first Saw it, I assumed that it was a fine crystolone stone.

It never occurred to me that this might be a water stone, so I applied some mineral oil that I have where I am, and gave it a go.

This very quickly pulled up a lot of mud from the stone. I had already been using a crstolone stone since that is what I have available.

This left a pretty nice edge and it did it pretty quickly, but I'd already worked it pretty well on the fine crystolone stone.

I will post and then see if I can add photos and a reply

[Andrew Pitonyak]

And now I will add the photos here if I can

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They're a little brads on the bottom so that the box will grab the workbench and it won't slide. There is a strop on top of the box. It looks like the box was chiseled out. There are two brads in the middle of the box so that the box top will catch on them and perhaps not slide around.

I can't tell which is which and this will be my first time uploading a photo from my phone, so we'll see how it goes.

[Jim Koepke]

Heck it even looks like the images didn't rotate as they often do from phone cameras.

jtk

[Andrew Pitonyak]

My first thought was that it might be An Hindustan, but I looked up a photo of one and it was a much lighter color.

[Luke Dupont]

Oilstones tend to darken a lot with use, so don't be fooled by color.
A lily white washita or Arkansas stone is often white as can be when you first get it, and becomes extremely dark with oil and age.
If you soak it in Simple Green or something to remove the oil, the true color might come out.

It most likely is an oilstone.

Could be sandstone?

You say it's muddy? Do you mean the stone wears a lot? Does it soak up oil really quickly?

[Andrew Pitonyak]

Although it did not seem to really soak up oil, it seemed to create a slurry of mud from the stone. Initially I thought I was removing metal like crazy until I realized that what I was getting off looked more like it was part of the stone and was surely not necessarily metal.

I thought it might be a sandstone, I also considered that maybe it's a water stone and I used oil on it... Given the packaging however it seems like it's a little on the old side for it to be a Japanese water stone again, based on the box it was in.

It feels very smooth and I thought maybe this is a razor hone. I have never used a razor hone. Not even sure I'm spelling that correctly.

So it looks like I'm raising a slurry as if I was using a nagury done (and I'm sure I spelled that wrong) but it seems to come right off the stone. The edge was decent.

I am out of state and so I purchased a crystolone from Ace hardware and it is not a Norton Stone and it surely was not working as well as my Norton's tones that are similar, but this particular stone left a much better edge than that fine side of the ace crystolone stone.

So, I don't think that it has simply absorbed a lot of stuff to get the color. Otherwise I don't think it would be kicking up such a slurry. It feels like a really fine stone.

[Rafael Herrera]

It could be a fine grit crystolon. A close up of the cracked area would help. If you can't see any layering in the cracked area, it may not be a sedimentary rock, like a slate. From other people's accounts, crystolon or carborundum stones from the Carborundum company were baked harder than what Norton is now producing. I have a few Carborundums, but not a fine one. I've yet to test that claim.

[Andrew Pitonyak]

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I own a couple of fine crystolone stones from a couple different manufacturers, and none of them are nearly as fine as the stone is. It seems to be as fine if not finer than the fine India, but it is significantly softer in that it pulls up a muddy slurry that looks just like the stone very quickly. The stone feels super super smooth.

It really feels more like a natural nagori stone (spelling)

It's a really weird stone.

Did they make an India stone that looks like that that might have been softer? Cuz my first thought was it's acting like it is mud.

[Rafael Herrera]

Is it smaller than a bench stone? Like 6x2x1/2 in? Fine synthetic razor hones are very fine and feel heavy/dense. I don't know what they were made of. The brand Swaty comes to mind. It could be one of those.

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[Andrew Pitonyak]

Is it smaller than a bench stone? Like 6x2x1/2 in? Fine synthetic razor hones are very fine and feel heavy/dense. I don't know what they were made of. The brand Swaty comes to mind. It could be one of those.

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I have never used a razor home, but I have one at home. I might find it when I get back to Ohio and give that a try see if it behaves the same.

This particular stone is 6x2 by at least 3/4 maybe a little more I'm not sure. I think my razor home at home is closer to half inch like you said.
It doesn't seem right given the age that this would be some kind of Japanese natural water stone. Which is why I used it with oil.

What do you usually use with a razor on? Water or oil I guess I don't even know

[Rafael Herrera]

I have never used a razor home, but I have one at home. I might find it when I get back to Ohio and give that a try see if it behaves the same.

This particular stone is 6x2 by at least 3/4 maybe a little more I'm not sure. I think my razor home at home is closer to half inch like you said.
It doesn't seem right given the age that this would be some kind of Japanese natural water stone. Which is why I used it with oil.

What do you usually use with a razor on? Water or oil I guess I don't even know

I don't use straight razors, yet.

The one Swaty I have, when I tested it, I used mineral oil, but I don't know if it was the right thing to do.

[Andrew Pitonyak]

Well whatever this tone is, it worked really well with the oil. Prior to the stone I had used a fine crystolone and although the edge was certainly usable on a kitchen knife, I wasn't really happy with it. When I used this unknown stone the edge was significantly nicer.

[Jack Dover]

This is a carborundum stone. "Crystolon" is just a brand name for carborundum.

The biggest quality factor for a synthetic stone is binder. Norton stones are great because they figured a good binding agent and can ensure it has uniform hardness throughout the stone. All other manufacturers will either have a soft spot somewhere on the stone, or they will be soft like dough and produce insane amounts of slurry. They're also not going to stay flat even for a minute. There are millions of stones like this.

[Andrew Pitonyak]

This is a carborundum stone. "Crystolon" is just a brand name for carborundum.

The biggest quality factor for a synthetic stone is binder. Norton stones are great because they figured a good binding agent and can ensure it has uniform hardness throughout the stone. All other manufacturers will either have a soft spot somewhere on the stone, or they will be soft like dough and produce insane amounts of slurry. They're also not going to stay flat even for a minute. There are millions of stones like this.

So you have used crystolone stones that behaved this way? I have owned probably 12 of these, but probably 6 we're Norton the rest were old and unknown brand. Never had one leave such a fine edge or work a fine slurry like that; but it did polish it pretty fast.

The Chinese made one I just purchased from Ace is not great.

I am just surprised how much finer and soft this stone is. I will admit, however, that the "chip" looks like it could be silicone carbide (crystolon).

Wish I had a magnifier with me, and I cannot take the stone with me when I head home.

[steven c newman]

I have about 3 up here for you to look over, sometime.....one is even in it's own wood tray....

[Jack Dover]

Yeah, carborundum stones with a soft binder will produce lots of slurry and since all the pores are filled it will produce a pretty high polish. It's like a glazed stone, except it still releases grit and therefore cuts, albeit slower. A prime example is Smith's 3 hone stone, which has two carborundum stones and a soft arkie. Both carborundum stones are insanely fast, the medium is also polishes to a bright mirror.

I, however, avoid such stones. Because of their softness they don't stay flat and they round a blade across its width. Not a big deal when a grinder is used, but if you're using a grinder once a month like I do it is somewhat annoying. Said Smith's sharpener was rounding over on a first sharpening and I had two carborundum stones worn down completely in 6 months or so, they were about 1/8" thick by that time. But oh my god, did they cut fast.

[Andrew Pitonyak]

Yeah, carborundum stones with a soft binder will produce lots of slurry and since all the pores are filled it will produce a pretty high polish. It's like a glazed stone, except it still releases grit and therefore cuts, albeit slower. A prime example is Smith's 3 hone stone, which has two carborundum stones and a soft arkie. Both carborundum stones are insanely fast, the medium is also polishes to a bright mirror.

I, however, avoid such stones. Because of their softness they don't stay flat and they round a blade across its width. Not a big deal when a grinder is used, but if you're using a grinder once a month like I do it is somewhat annoying. Said Smith's sharpener was rounding over on a first sharpening and I had two carborundum stones worn down completely in 6 months or so, they were about 1/8" thick by that time. But oh my god, did they cut fast.

You just described this stone pretty precisely. The slurry it raises is very fine and the stone is so smooth I never would have considered it as such.