Hey Rusen, you know under Peters Terms this is only a small pepple of stone *laughs*
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Well i know , but every time i see a 12 x 3 x 1 .5 inch thuri , i feel bad ha ha ah
Well this small piece of rock (it actually isn't that large only about 25 x 9 cm :nono:) has enormous sharpening power. A knife produces black swarf in only a few strokes...
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I had to check twice if I didn't confuse the boxes and grabbed one of my Dalmore blue/ yellow hones instead of a thuri. And in fact, they look quite comparable (especially the broken one on the left side):
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If this thuri will also be as fine as a yellow-green standard Escher I might have found a new class of thuringians ....
So it is a small 10 x 4 inch thuri. I understand now , mhhm :hmmm:
Well it is my mistake
That is an excellent picture, and I always thought that the Thuringian Escher is of green color. HAttachment 253597 Here's one characteristic....if left unused, it tends to discolor its green color, and becomes grey in time.......this thuri is about 5.6"X1.5"X1/2"
Don't really understand what you mean. Thuringians don't tend to discoloration in any way in normal atmosphere and sunlight. The only way you can create discoloration is by impact of stronger acid substances.
The color change in thuringins is based on the change of layers. Since the layers undergo a certain shifting and bending during their formation and millions of years of appearance, the layer lines are not always straight, they sometimes turn into each other and mix with each other.
The grey color of thuringians is a very typical color for a specific layer and it appears very often. There are nearly all other shades of green, grey and up to yellow and of course blue. The grey colored one were always classified as light green in former times.
The one I have was purchased a long time ago....25-30 years ago. The thing is, I misplaced it somewhere, and lost track of it. I found it recently, about 8-10 month ago, and it looked grey. After I lapped it on an Atoma plate, the side I'm using, became green again. The first picture depicts the backside of the stone, and I cleaned it with a 1000 grit sandpapaer, and you can see the difference. Now maybe the extended time in its box discolored it and that's where the grey color is, but the side I lapped it is green This picture depicts the side I'm using and it is of a green color Attachment 253708
Iam also not sure what he mentioned but actually i experienced sometimes that the stones are kind of fatty why beeing used with anything. In the beginning it often looked like oil was used, when you lap the stone you can easily see that the original surface was much more discolored then the layer beyond. You actually can see how water moves over the stone and doesnt stand on the stones surface...
Sounds like an oiled thuringian...
I experienced this in many cases probably with 5 or 6 stones. But in the end after lapping really short and only remove the first discolored layer nothing of this "oily" behavier has left. So im sure no oil was used on the stone...
On the other hand, if oil was used, and it soaked in the slate as often told or described it woudnt be possible to kind of restore it.
Did you Peter or someone else here ever experimented what happens when Thuris are really fully oiled? We know that other dense slates or other hones might show a behavior not to soak in oil
Another Thuri beauty i would recall that one. Very fine and smooth stone. And actually a very rare three layer example....i just love it!!
Barbers Delight Quality and size in 6x2inch.
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Yes, I have seen that when prolonged soaking in cleaning solution. I use Simple Green and water, a degreasing product and sometimes soak for months changing the solution every week or so.
They do lighten up in color but the color returns with lapping. I have always suspected it was caused by the dirt and impurities that were released during the soaking.