For sale is a Belgian Yellow Coticule purchased from Joel in THIS thread, down at item #4. (This thread was in the contributor's forum, so non contributors will be unable to view it... Thus, the description has been cited below)
"Item #4 - Vintage Belgian Kosjer Stone - These are technically not even considered coticules and this vintage stone in particular is exceptionally thick and wide (typically this layer is VERY thin, and the amount of usable stone you get is just a sliver, however this one you get a very generous amount of stone) and of the highest quality - which you can no longer get of this size/quality as the stones this good have been mined out 50+ years ago. This stone is from the "La Petite Vein" and is called an "Old Rock" Kosjer in which the shales enclose a little discontinuous white bed near the coticule layer - EXCELLENT quality. Size = 5 1/8 inchs long by 2.5 inches wide. I'll likely only offer this up for a day or so as i'm really quite fond of this stone. It's the finest natural stone i've ever used (blows away a yellow gold escher - which I also have) and is among the rarest you'll find. Has original faint "Made in Belgium" stamping, and the stone is secured on a VERY dense/robust piece of slate - much heavier/more robust than what they currently use. Stone is lapped and ready for use."
The stone is incredible, but I need to switch to a more affordable option.
Asking $400 Shipped USPS Priority.
Price includes shipping to CONUS. International, please inquire.
I will accept payment through Paypal, or Money order if you wish.
Pics, from Joels Thread: