The Black Stone (, , 'Black Stone') is a rock set into the eastern corner of the Kaaba, the ancient building in the center of the Grand Mosque in Mecca, Saudi Arabia. It is revered by Muslims as an Islamic relic which, according to Muslim tradition, dates back to the time of Adam and Eve. 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 Islamic 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 to kiss the Black Stone, emulating the kiss that Islamic tradition records that it received from Muhammad. While Muslims revere the Black Stone, they do not worship it. Physical description The Black Stone was originally a single piece of rock but today consists of several pieces that 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 by . 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 () long. By the early 17th century, it was recorded as measuring . According to Ali Bey in the 18th century, it was described as high, and Muhammad Ali Pasha reported it as being long by wide. The Black Stone is attached to the east corner of the Kaaba, known as al-Rukn al-Aswad (the 'Corner of the Black 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