Black Stone (al-hajar, al-aswad) is a stone believed to be of meteoric origin. Its composition is thought to be of lava or basalt; it is reddish in color, and is embedded in the eastern corner of the Ka’ba in Mecca. The Black Stone is considered the holiest object in the Ka’ba. During the hajj (pilgrimage) the pilgrims attempt to kiss or touch the Black Stone as they walk around the Ka’ba seven times. A.G.H.
Bowker, John, The Oxford Dictionary of World Religions, New York, Oxford University Press, 1997, p. 152