A friend recently returned from a teaching trip to Turkey and amongst the gifts that she was given and the end of her courses were 3 sheets of marbled paper. This is the one that I particularly like, the image being somewhat organic. I can see a cross section of a plant or algae perhaps.
I'm not so keen on this one, as I find the red too dominant, however I'm sure that a bit of inversion in Photoshop, which would change the red to a turquoise blue, would be an improvement.
This is of course is a more traditional design in marbling, the sort of pattern that one would see as end papers in old books. Made with a very fine toothed comb dragged though the floating inks, it's a beautifully detailed piece of work.