The team of color scientists hovered in their white coats and hairnets, staring down at a clear plastic box full of strangely colored M&Ms. “They look like pebbles, ugly little pebbles,” said Rebecca Robbins, the color-chemistry manager for Mars Chocolate. She propped open the lid to show off a muted array of gray, tan, mauve, pale purple and sickly pink chocolate nuggets. Each attenuated shade was the disappointing outcome of an early attempt by Mars to replace a bright, artificial dye with natural pigments extracted from algae, roots, seeds and other parts of plants. Not a single piece of candy in this tackle box of failure looked edible — let alone tempting.
Noticeably absent was any M&M that even vaguely resembled blue, the most coveted, and hardest to find, of colors. Blue is a rarity among plants and animals. When it does occur in nature, it often isn’t truly blue, but rather a trick of diffraction, or the scattering of light, which is the case for bird feathers, sky, ice, water and iridescent butterfly wings. A blueberry is actually more red than blue when you mash it. “Unfortunately, you can’t just grind up a peacock feather,” said Robbins, a petite woman with a Ph.D. in organic chemistry and the empathic, wide-set blue eyes of a small-town bartender, with what sounded like genuine regret.