What do you reckon this stone is?

[Trevanion]

I’ve been having a bit of a clear up and I came across this oil stone plastered in a thick layer of dust so I decided to clean it up a little to see exactly what it is, to be honest I haven’t got a clue what I’m looking at, perhaps a Washita or Arkansas? I don’t think it’s man-made, it has a hell of a taper along its length to the width of the stone which looks like it was cut that way with a reciprocating saw of some kind.

 

[MIGNAL]

I've always associated that mottled appearance to a Washita but I'm far from being an expert. Doesn't help when I've never actually used or seen one in real life. I have a Smiths Arkansas, doesn't look anything close. DW is your man, I'm sure there are others on the forum who can help.
Pity about the chips but it can still see service.

 

[Ttrees]

I've got a soft Arkansas and a washita and neither look like that, dry or wet,
wet as in both water and thin oil.
In your first photo...
The portion on the upper right with the khaki colour, guessing this had the most cleaning done to it?

With the two stones I have, I found the best way to I.D them is by abrading them dry as water brings out the mottle, which can mimic another stone.
The soft ark covered in oil and used briefly, can look like a washita, but when both are clean and dry the washita looks more like chalk to me.
The same soft ark will have a golden mottled glow to the stone when clean and dry.

The closest thing I've seen to that was on some of Bill Carter's videos.

If I'm not mistaken, he regards these as the best he's ever used.
Surprised he doesn't know what it is, with all the research he does.

Curious to know what it is
Thanks for the pic

Tom

 

[Trevanion]

I decided to flatten the one side that was pretty flat anyway with a diamond plate in the hopes that it would clarify the surface a bit, the other side has a 3-4mm bow in the length of the stone.

The stone seems to actually be much harder to lap with the diamond plate than the Washita I did last time, it leaves a kind of white chalky dry paste on the diamond plate which needs to be wiped off occasionally. I lapped the stone dry.

Here's the stone wetted with WD40, the stone seems sort of permeable because the WD40 seemed to disappear quite quickly.

Initially, I thought the lines on the side of the stone were saw marks hence why I thought it had been cut with a reciprocating saw, however, I see now that this is actually some kind of "grain" to the stone a bit like how wood has a grain, perhaps this will help identify it?

I'm not 100% sure whether the stone is absolutely clean, I've been dousing it with Meths and scrubbing it with a Scotch-Brite pad which cleaned some of the grime off but I'm not sure whether some of the markings are grime or just the natural stone.

It feels pretty smooth and trying it on a chisel it brings up a keen edge shaving edge without needing to strop it although a strop would finish it off much better. I'm still none the wiser on what it actually is though, some kind of sandstone perhaps?

 

[Droogs]

the marks are called striations and show the layering of sedimentary rock particles. Each layer represents anything from 1000 years to several 10ks of dust slowly settling to form the rock

 

[Sean Hellman]

Hindostan stone from Indiana. I quite like them. Do an internet search for more info, lots out there.

 

[--Tom--]

My first thought was Hindostan too

 

[Bod]

A method of cleaning an oil stone, that I've had success with, is to use "Swafega" type hand cleaner, scrubbed in with a dry nail brush, before washing with ordinary hand soap.
The beaded hand cleaners work even better.
Keep the stone dry first, only use water to rinse after the scrubbing.

Bod

 

[Jackbequick]

Not much intelligent I can add, the photos don't tell much If it bows in the middle it was used for putting edge on a blade of some type. The texture where chipped in some places looks to me like lead or galena and oddly enough reminds me of phosphorus. Only the galena is a harder metal of those three. It may be volcanic as opposed to sedimentary. Your Iocal geologist would be the person to ask.