Thread: Mystery Stone.....any guesses?

Yes, slate can be multicolored: Banded slate whetstones

The clay smell and uniform gray color suggest slate, or rather continue to rule out Arkansas. Do you have a Coticule with a slate back that could maybe serve as reference?

From the wikipedia description of slate: " Occasionally, as in the purple slates of North Wales, ferrous reduction spheres form around iron nuclei, leaving a light green spotted texture. These spheres are sometimes deformed by a subsequent applied stress field to ovoids, which appear as ellipses when viewed on a cleavage plane of the specimen."

..."Fine slate can also be used as a whetstone to hone knives."

So from those pics, it looks like you have a purple-ish/gray stone with green inclusions, almost exactly as is described above for Northern Wales Slate.

Yes, I have several slate bonded coticules. I think you're right, Russel. This stone is most likely a multi-colored slate. Cool.

Chris L

Great, now I have to get a piece for myself!

I've known about them for some time but ruled them out as good options, but if you say it polishes steel, it's worth a try. I wonder how long it would take to lap a floor tile, or maybe there are different grades.

You'll have to report back on this, very interesting.

I'll report back. I'm anxious to get enough time to really use it for edge polishing. It definitely polishes steel since it was used for years in a diesel shop to lap steel injectors flat.

The few passes I did on a razor just to see how quickly it altered a coarse stone scratch pattern looked like it might be a very.....slow.....polisher. But, I did not use slurry, etc. so experimentation is definitely necessary.

Chris L

I have what was advertised as a Wa****a stone that is oddly colored. It produces a purple slurry very similar to my BBW. It's a slow cutter/polisher and feels 'soft' on an edge.

Huh, I've never had an Arkansas stone that did that.

You learn something everyday.