Escher stone

I have an old Escher stone 8"x1 3/4" x 3/4" a few small slivers around the edges have started to come away I have made a box for it and have never dropped it One such sliver measures 3/4" x 1/32"
It seems to delaminate of flake of. I dont want to keep lapping to a flat portion in case it encourages more pieces to do so. I try to avoid using that area. Has enyone experience of this is this common if so can I prevent this happening, :shrug:is it just inherent of this stone or could it just be a flaw. I understand it is a sedimentary rock and perhaps some of the layers have not bonded when it was formed. Anyone have experience of this happening to them or ideas why it is happening

Can you post a pic?
For sealing the sides and prevention of splitting I'd lacquer the stone.

Thank for that I'm not to clued up on posting pics just yet, I have a few other stones and this is the only one showing signs of splits any idea of cause ? I would have not have thought moisture or frost would cause this it certainly has never been frozen. I have only recently obtained this one superficially it seemed ok perhaps it may have been roughly handled in it's past, it was certainly never used and perfectly flat but slightly pot marked I almost passed it by but after lapping flat it was as smooth as glass and gave a good edge. Would the lapping have released any stresses that may have caused this?

I've never heard of an Escher acting like that. Slate, Mica for example do that kind of thing. Are you sure it's an Escher?

Quote:

---

Originally Posted by thebigspendur

I've never heard of an Escher acting like that. Slate, Mica for example do that kind of thing. Are you sure it's an Escher?

---

I'm wondering the same thing. An escher/vintage thuringian shouldn't be flaking or delaminating. A slate stone certainly can.

Quote:

---

Originally Posted by thebigspendur

I've never heard of an Escher acting like that. Slate, Mica for example do that kind of thing. Are you sure it's an Escher?

---

My thoughts exactly, Doesn't sound like Thuringinan/Escher to me...Pics would be very helpful.

I have a thuringian that I recently obtained that has had a rough life and one of the chips on a corner looks like it chipped at either a natural inclusion or "layer". If it is a thuringian it may have been dropped or been almost crushed edgewise causing this phenomenon to happen. Who knows what has happened to a stone before it came into our possession. Sealing it with several layers of a sealant like polyurethane or high build lacquer may help it & sure won't hurt it...but as these guys have mentioned it is almost impossible to diagnose a problem without pics...this is intriguing...

Thanks guys I can't be 100 per cent sure it is an Escher or thuringian but I do posses a genuine escher waterbhone in it's small wooden box and light blue label with the goblet, this stone I m having problems behaves very much like it giving a good mirror polished edge. I t may be the case that it is slate but would you still get a fine edge of slate. Years ago when I started my apprenticeship as a wood pattern maker I got a Mason to cut me a piece of slate the size of an oilstone it was great for sharpening planes chisels etc I treated it roughly but it never behaved like this. Would slate be fine enough to produce an edge comparable to an escher? I ll try and post some pic in the next few day. I t didn't cost me a great deal in the region of £5.00 or 7 dollars so it's purely curiosity as to why this could be happening.

I thought Thuringians were a genus of slate. They are sedimentary rock at least. Can slate leave a polished edge? The Yellow Lake Oilstone is a finisher comprised of slate that improves the edge left by my Naniwa 8k and certainly leaves a polished edge. It could be comparable to an Escher in that it is a finisher after 8K.

Quote:

---

Originally Posted by Scipio

I thought Thuringians were a genus of slate. They are sedimentary rock at least. Can slate leave a polished edge? The Yellow Lake Oilstone is a finisher comprised of slate that improves the edge left by my Naniwa 8k and certainly leaves a polished edge. It could be comparable to an Escher in that it is a finisher after 8K.

---

Not to take a thread off the main topic - but how do you use your yellow lake? I'm assuming with oil. I bought one over a year ago in a state of HAD and never got around to giving it a try. Might have to break it out and see how it performs after a coticule.

So far I've used it on one old French wedge and it gave a great shave. 50 laps, water only. I'm going to try it with oil to see how it improves the edge.

In the absence of any pictures of the stone in the OP, the thread is virtually precluded from progressing as they are greatly needed, so not to take the thread even further off the main topic, what's a coticule?

Quote:

---

Originally Posted by Scipio

so not to take the thread even further off the main topic, what's a coticule?

---

Coticule' is an umbrella term for any rock once mined at various sites across Belgium and now only Ardennes ranging from green to pink in colour, more commonly a shade of yellow. The natural patina and imperfections do not in any way affect the properties of the hone. :D

I don't know that anyone has ever given an analysis of the rock itself on the site. My guess and it's only that is the light colored coticules are based on some Silicate minerals making it up. Certainly there is a relationship between the garnets which are silicates and the rest of the stuff.

We do know its a metamorphic rock with garnets contained within and the garnets are responsible for most of the cutting action.