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Unidentified rock


Well-Known Member
Got this small piece of rock,dont know what it is...a coti or maybe arkansas??
It was my grandfathers and very likely his fathers as well- they were both carpenters- and he used it for honing tools and have used it for some 50 years or so. It measures 70*55*15 mm. It produces a white slurry when used as a slurry stone,and thats what I use it for :| It has a very smooth surface that cuts very fast with slurry.



I took the liberty of downloading one of those pictures to my computer. I lightened it up and corrected the white point, with the one assumption that your background has a neutral color.

Please tell me if it still looks like your stone:

If it does, it can very well be a piece of raw Coticule.
Please try creating slurry from the blue part. If the results has the purplish hue of a BBW, it's likely a Coticule.

Best regards,
Hi ..Pics were taken with a cell-phone..please see the first post again,the pics are a bit better now.
The small blue part of the stone does create a purplish slurry..the rest of it - at least the lapped surface doesnt look like the cuti`s I`ve seen on this site...Though I have absolutely no experience with coticules what so ever.
...But ordered a coti from the Ardennes today...Rob sends a slurry stone too,dont know if that is custom but I mentioned your name Bart ;-) thanks for answering..And that fat old lady you kindly offered to hone is comming along ...very slowly but at some time it might get ready :thumbup: