Hello,
I have an interesting coticule I bought in a shop near me. It has an interesting pattern on top and on the side you can see that the pattern changes to some smooth looking part. On this part it also has some layers, wich appear to be bluish. It also has a fault at the bottom wich is filled with the bonding material, which I suspect is resin. The Coticule part is also quite large, about 12-14 mm. The other dimensions are 40x150mm. I got it with a label from Robert herder, Windmuehle Messer.
I think it might be la verte, la grosse jaune or la grise, but I don't really know. Also the stone is quite slow. On slurry it took more than one set of halfstrokes (20 each side) before some discoloration could be seen.
https://blunon2.uber.space/images/coticule2/1.jpg
https://blunon2.uber.space/images/coticule2/2.jpg
https://blunon2.uber.space/images/coticule2/3.jpg
https://blunon2.uber.space/images/coticule2/4.jpg
https://blunon2.uber.space/images/coticule2/5.jpg
https://blunon2.uber.space/images/coticule2/6.jpg
https://blunon2.uber.space/images/coticule2/7.jpg