The unique dZi beads, a black-and-white (or dark brown) bead of "etched" or treated agate, is revered in Tibet. To Tibetans and other Himalayan peoples, the dZi is a "precious jewel of supernatural origin" with great power to protect its wearer from disaster.
Since knowledge of the bead is derived from oral traditions, few beads have provoked more controversy concerning their source, method of manufacture, and even precise definition.
In ancient times, it is said dZi adorned the gods, who discarded them when they became blemished, thus explaining why they are seldom found in perfect condition.
[Source: The History of Beads, 2009]