The stone was venerated at the Kaaba in pre-Islamic pagan times. According to Islamic tradition, it was set intact into the Kaaba's wall by the prophet Muhammad in 605 CE, five years before his first revelation. Since then it has been broken into fragments and is now cemented into a silver frame in the side of the Kaaba. Its physical appearance is that of a fragmented dark rock, polished smooth by the hands of pilgrims. Islamic tradition holds that it fell from heaven as a guide for Adam and Eve to build an altar. It has often been described as a meteorite.
Muslim pilgrims circle the Kaaba as a part of the tawaf ritual during the hajj and many try to stop and kiss the Black Stone, emulating the kiss that Islamic tradition records that it received from Muhammad.
The Black Stone was originally a single piece of rock but today consists of a number of fragmented pieces which have been cemented together. They are surrounded by a silver frame which is fastened by silver nails to the Kaaba's outer wall. The fragments are themselves made up of smaller pieces which have been combined to form the seven or eight fragments visible today. The Stone's exposed face measures about 20 centimetres (7.9 in) by 16 centimetres (6.3 in). Its original size is unclear and the recorded dimensions have changed considerably over time, as the pieces have been rearranged in their cement matrix on several occasions. In the 10th century, an observer described the Black Stone as being one cubit (46 cm or 18 in) long. By the early 17th century, it was recorded as measuring 1.40 by 1.22 m (4 ft 7 in by 4 ft 0 in). According to Ali Bey in the 18th century, it was described as 110 cm (3 ft 7 in) high, and Muhammad Ali Pasha reported it as being 76 cm (2 ft 6 in) long by 46 cm (1 ft 6 in) wide.
The Black Stone is attached to the east corner of the Kaaba, known as al-Rukn al-Aswad (the Corner of the Stone). Another stone, known as the Hajar as-Sa’adah (Stone of Felicity) is set into the Kaaba's opposite corner, al-Rukn al-Yamani (the Yemeni Corner), at a somewhat lower height than the Black Stone. The choice of the east corner may have had ritual significance; it faces the rain-bringing east wind (al-qabul) and the direction from which Canopus rises.
The silver frame around the Black Stone and the black kiswah or cloth enveloping the Kaaba were for centuries maintained by the Ottoman Sultans in their role as Custodian of the Two Holy Mosques. The frames wore out over time due to the constant handling by pilgrims and were periodically replaced. Worn-out frames were brought back to Istanbul, where they are still kept as part of the sacred relics in the Topkapı Palace.