Thread: Coticule speed

Is there a thread discussing how to determine the speed of a coticule or are such appraisals too subjective to be of use?

Probably dozens if you do a forum search. Weeding out the posts relating to speed might be a chore since 'coticule' would bring up all sorts of results. IME coticules with pink or light magenta hue, amidst the yellow tend to be faster than average. People will generate a slurry and the quicker it shows gray for metal residue the faster the coticule.

Green hues in a coticule tend to be hard and slow but , in the case of one that came my way from South Africa, a really fine finisher. Other than taking the individual stone and trying it I don't know that you can say this vein or that vein will be characteristically fast or slow. Which doesn't mean that you can't do it, just that I don't know if you can.... reliably. Our SRP library, formerly known as the wiki, had some good stuff in there on coticules. I don't know if it is still there , or if it may have been edited..

The only way to judge the speed is to take a razor to it. They vary a lot.

I agree with Jimmy, green ones tend to be slow and fine and pinkish hued variants are faster, but as Startibartfast said: you have to take a razor to it to know. I have had 11 different coticules and the fastest was a small yellow one with black manganese lines which I sold to a member here. It was small and while it was a fine finisher for a coitcule, I have larger ones. It was quick - 10 circles would turn slurry black. Here is a picture of it next to a green coticule that would not cut at all, no matter how many circles I did. It would only polish. The differences among samples can be gigantic. Some are like different stones. I once said 'coticule' is a generic term describing any rock ranging from pink to yellow in colour containing garnets mined across Belgium and now only Ardennes.

i have a few coti's (lol) and dont like to associate the colors of them with performance, but most of the coti stone do fall in with the stereotype performance pink, red, brown, fast cutters yellow is mello and green is slow hard and fine
Disclaimer they are natural stones so the stereotype performance isn't always right.

I would not consider this one as fast. Perhaps one of those exceptions.

wow thats a looker how the performance on that stone ?

Not that fast and about 4000 grit. but it could be me not unlocking full potential.