I am usually one to say pop the colors out but with this design, I rather like this version as compared to your richer color version. It's lighter but still colorful and it reminds me of a pattern one might well see in marble or slate.
wow, i can really see the marble idea now. maybe i can work on another version of it with a marble color gradient, so it actual looks like (or close to) marble. thanks for all the wonderful comments!