I quite often just run stone textures through EZSkin2, with the SSS option in the second tab changed to marble... and any stone textures in the figure / prop set to "Skin".

Depends if you're using Poser 9 / 2012 or above though... as it needs that SSS node.

It's a fairly lazy and inappropriate method probably... but looks okay to me usually, when I use it ;-)

I used this technique on the statue in my latest gallery post...

http://www.renderosity.com/mod/gallery/index.php?image_id=2485786

...of course that statue model came with a beautifully painted texture to begin with... so the SSS is just giving it a little more zing, I think.