Ok made a cool bump-function and am rendering now.
It's quite a bit slower with this extra detail, so if one doesn't use these stones for close-up then disabling/deleting this part will increase renderspeed quite much. That will be documented of course
I'm open to suggestions from all of you on what kind of colour-setting you'd like to see in my next stones shader.
As I said I am planning to make 3-4 different shaders and pack these up. I have a couple of variations in mind, but I'd be happy to hear what you would like to see included. Maybe if things keep on developing as relatively easy as now I might be able to end up with more than 3-4 shaders, who knows
Cheers,
Martin