Chiastolite
Chiastolite is a form of andalusite. It is also known as the “cross stone,” or “piedra de cruz,” due to its cross-like inclusions of graphite. Its name comes from the Greek word, “chiastos,” for “cross-marked.” Chiastolite has been used since ancient times for protection. Contemporary stone lore rumors that Chiastolite is also worn for balance and harmony, and is thought to enhance the intellect.