Dremel grinding wheels?

[gareth evans]

With the Dremel are three different colours of grinding wheels,
white, green and a sort of pinky-brown.

Does anyone here know what each colour is used for?

TIA

[Peter Fairbrother]

Someone once told me that the blue-grey ones were for very hard
materials. When I tried they crumbled though, maybe my technique was bad.

Peter F

Post by gareth evans
With the Dremel are three different colours of grinding wheels,
white, green and a sort of pinky-brown.
Does anyone here know what each colour is used for?
TIA