The coticule is a great stone. You can either use it in combination with other stones as a finisher by using just water on the hone (they are known for leaving a very smooth comfortable edge), or you can work up a slurry and use it for all stages of honing (this takes a bit of time to learn how to do, Bart has posted some threads on how to do it).

You'll find coticules in two configurations. One has a slate backing (for strength, not to use as another hone), the other is a "natural combo" which has a yellow coticule on one side, and a belgian blue on the other. These combo stones cost more, but have a lot of character, and you can use the belgian blue side to hone as well.

If you want to learn more about these hones, you can also go to Bart's coticule site: www.coticule.be.

-Chief