For thousands of years the image of the rainbow was pecked and painted by native Americans onto the rocks of the Great Basin and the Southwest. This long-lived tradition, which transcended major developments in lifestyles and cultures, underscores the important symbolic significance of the rainbow to the inhabitants of this arid region. The rainbow rock art depictions were usually associated with humanlike ceremonial figures, snakes, clouds, rain, and lightning bolts, suggesting that the rainbow symbol was employed as part of an elaborate sacred tradition. Although such ceremonial usage of the rainbow image tends to lead to abstraction and symbolic representation, there are examples, including a properly colorized rainbow painting from central Utah (approximately a thousand years old), that indicate observationally based rainbow reproductions of relatively great antiquity.
© 1991 Optical Society of America
Kenneth Sassen, "Rainbows in the Indian rock art of desert western America," Appl. Opt. 30, 3523-3537 (1991)