The Black Stone (al-Hajar al-Aswad) is a dark, venerated stone set into the eastern corner of the Kaaba, the cube-shaped building at the heart of the Masjid al-Haram in Mecca toward which Muslims turn in prayer. Now in several fragments held within a silver frame, it stands about waist height at the corner where pilgrims begin the tawaf, the sevenfold circling of the Kaaba during the hajj and the umrah. Following the practice of the Prophet Muhammad, pilgrims try to kiss the stone, touch it, or, in the crowds, raise a hand toward it in salutation.
Islamic tradition regards the stone as belonging to the sanctuary from its founding by Abraham and Ishmael. Its identity as the honoured stone of the Kaaba has been continuous and is not disputed, which is why it is classed here as attested. A separate and much narrower question, what the stone is made of, and where it originally came from, has intrigued geologists, but because the object cannot be removed or sampled, that question remains open. The stone's religious meaning is independent of its mineralogy.