I've been experimenting more and more with "natural" food colorings - meaning spices and other ingredients that naturally impart color as opposed to a commercial food dye made specifically for this purpose.
For example, I've let scallops (among other things) sit in a beet puree, and they get a brilliant pink color. I plan on trying turmeric and saffron for more yellow/orange/red colors.
Are there other ingredients that I can try that might create a green or blue color in scallops? And would these work for other foods as well?