Author Topic: Please can anyone ID this natural sharpening stone ?  (Read 435 times)

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Offline rustyric

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Please can anyone ID this natural sharpening stone ?
« on: November 25, 2019, 04:11:00 PM »
Its grey (or gray to you guys across the pond:-) with a lighter grey speckle. Found at local flea market covered in congealed oil.




Offline wvtools

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Re: Please can anyone ID this natural sharpening stone ?
« Reply #1 on: November 25, 2019, 05:07:06 PM »
I was actually a geologist before I was a tool guy, but it has been a long time since I was a mineralogy teaching assistant.  It looks like a siltstone with quartz sand grains, but it is hard to tell from a photo.  Can you see if it will scratch glass?  It would help if you could try to isolate the dark gray and light gray particles when scratching to see if they both do or just one.

Offline rustyric

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Re: Please can anyone ID this natural sharpening stone ?
« Reply #2 on: November 26, 2019, 03:57:55 AM »
Ok I will give it a try

Offline rustyric

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Re: Please can anyone ID this natural sharpening stone ?
« Reply #3 on: November 26, 2019, 03:55:37 PM »
I have tried the scratching glass test. The darker grey areas are scratched with the glass, and the pale grey areas (the small speckles) scratch the glass. Hope this is helpful.

Offline wvtools

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Re: Please can anyone ID this natural sharpening stone ?
« Reply #4 on: November 26, 2019, 05:20:58 PM »
It is hard to tell from the photos, but it is probably a very fine siltstone with quartz sand grains in it.  It looks like a sedimentary rock from the photos.  It seems like an odd choice for a sharpening stone.  A more homogeneous stone would probably work better.  Most of your rough sharpening will come from the side with the most grains.  I would use the side that is darker with fewer grains for finer honing.

Offline p_toad

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Re: Please can anyone ID this natural sharpening stone ?
« Reply #5 on: November 26, 2019, 10:36:55 PM »
might be related to the belgian blue stones...