Since Robin's Eggs stain your fingers so badly (I think I've seen kids use them as lipstick before) I figured they'd be great for chromatography. Sure enough, the color showed up nicely--well enough to show that there was no separation. The colors I tested (pink, yellow, and blue) were all pure dyes, not mixed.
Blue Robin's Egg Dye--Just Blue
"You should have known that already," my daughter scolded, saying I'd wasted my time. "After all, you're the candy experimenter."