One of the world’s most coveted gemstones, opal’s name evolved from the Roman opalus which was derived from the Greek opallios, meaning “to see a change of color.” The Greek word was a modification of the ancient Indian Sanskrit name for opal, upala, which meant “precious stone.” Opal's unique qualities have attracted the attention of many ancient civilizations – and still do.Opals possess flashes of rainbow colors that change with the angle of observation, called play of color.