When the conditions are right, a rainbow doesn’t necessarily have to contain red, orange, yellow, green, blue, indigo, and violet. In fact, it’s entirely possible for the cooler shades to disappear ...

Blue is one of nature's rarest colors. Indigo, a dye obtained from the tiny leaves of small parasitic shrubs that are part of the Indigofererearsa tribe, creates the bluest of blues. For almost five ...