Help with hone ID please!

I picked this up at a Brussels flea market in the same box as a rusty and unusable old straight razor (not the one pictured which is just for scale); green/brown color, quite soft and slurries easily like a coticule (I used a credit card diamond hone) but the slurry seems finer than the coticules I've tried and this one has no backing either. The seller was a dealer from France. I lapped the surface which looked very much like the bottom (but with a deep dip from honing). Produced a very nice grippy edge on two razor refreshes. Any information gratefully received, thanks gents!



http://i1084.photobucket.com/albums/...psklifk7c4.jpg


http://i1084.photobucket.com/albums/...psnevi8wha.jpg

http://i1084.photobucket.com/albums/...pss9qesqmp.jpg

Possibly one of those Pierre du Sud Ouest or whatever they're called.

Hey, a nice narrow stone! I agree with eKretz here. Those stones act like coticules and are a little bit finer. Sort of a brown/ochre, as I recall.