David Weaver
First, the coarse coticule - these are a cream colored belgian stone with natural garnet articles in them - their boast is that the particles are round and more gentle (at least that's how they're framed for razors).

At one point, 7 companies were mining these as they also come with belgian blue stone mining. The blue and yellow seams meet and the combination is a natural yellow stone (unstable) with a blue stone backing (stable).

Now, one company mines them and for the price, they're not worth the hassle. They are all massively different from one to the next, though "select" grade stones are fine enough for finishing edges. But they could be fast or slow, you'll never know, and a large bench stone size will be less fine than an oilstone and could cost $300.

The first coarse stone is fast enough that it could be used for woodworking, but it's size is only about 2.75" x 5.5" and it's sort of irregular. Even this size is $100. I'll spare everyone the nuances that make it worth having one for razors.

notice how shallow the grooves are from the round particles. you can actually see the bottoms of some of the grooves, which isn't common in short field of depth. This stone blackens swarf quickly. Maybe the fastest of these I've had (out of about 15).

The large articles still slurry dull the edge a little bit.

And next is a fine coticule - this is an older stone of mine. It's extremely slow, which is useful for razors, but only after another finish stone. worthless for woodworking.

notice the slurry dulling is less, but still not a great combination for use.

George stocked this at CW because there were a few european tradesmen who used them. They spit on them (they can be used with water or oil, but most are used with water now - oil is a good way to see if a crappy one will do better on oil than water, and it doesn't go deeply into them as they're not porous).

Fun fact, showing a label that said "with water or oil" on a vintage coticule and stating that using oil on them is fine could get you banned from a shaving forum that I was on because one of the moderators said at one point they couldn't be used with oil (he didn't feel obligated to learn whether or not that was true) and maintained that it would be the rule by banning anyone who said otherwise.