Rudraksha (IAST: rudrākṣa) refers to a stonefruit, the dried stones of which are used as prayer beads by Hindus (especially Shaivas), as well as by Buddhists and Sikhs. When they are ripe, rudraksha stones are covered by an inedible blue outer fruit so they are sometimes called "blueberry beads". The rudraksha stones are produced by several species of large, evergreen, broad-leaved tree in the genus Elaeocarpus, the principal species of which is Elaeocarpus ganitrus.