NOOBish question - trying to find a decent cycles marble/cast iron texture...

Hi all
I’ve been trying to get a decent set of sculptured effects for some models I’ve designed. I want to make variations looking like carvings in stone/marble and as if cast as a classic metal scuplture

The examples of textures I’ve found aren’t particularly effective, but I do see lots of tests by seasoned ‘Blenderers’ who have created fantastic sculptural models.
These are great!
http://zbrushfun.wordpress.com/tag/marble-bust/
http://zbrushfun.wordpress.com/tag/blender/page/10/

Does anyone know of a good material and node setup example that I could follow to create my own variations for Stone/Marble and castings?

As always, any help is very much appreciated!

Thank you
Sanjay