The Black Stone (called al-Hajar-ul-Aswad in Arabic) is a Muslim object of reverence, which according to Islamic tradition dates back to the time of Adam and Eve. It is the eastern cornerstone of the Kaaba, the ancient sacred stone building towards which Muslims pray, in the center of the Grand Mosque in Mecca, Saudi Arabia. The Stone is roughly 30 cm (12 in.) in diameter, and 1.5 meters above the ground.
When pilgrims circle the Kaaba as part of the Tawaf ritual of the Hajj, many of them try, if possible, to stop and kiss the Black Stone, emulating the kiss that it received from the Islamic prophet Muhammad. If they cannot reach it, they are to point to it on each of their seven circuits around the Kaaba. The Stone is broken into a number of pieces from damage which was inflicted during the Middle Ages. It is now held together by a silver frame, which is fastened by silver nails to the Stone. Devout Muslims believe the Black Stone should be less accessible to the general public, as a way of protecting such a relic.According to Islamic tradition, the Stone fell from Heaven during the time of Adam and Eve, when it was a pure and dazzling white, but has since turned black because of the sins it has absorbed over the years. It was later removed and hidden in the hill of Abu Qubays near Mecca. When Abraham rebuilt the Kaaba, the Archangel Gabriel brought the Stone out of hiding and gave it to him. The Black Stone has been described variously as basalt lava, an agate, a piece of natural glass or — most popularly — a stony meteorite. It is evidently a hard rock, having survived so much handling. A significant clue to its nature is provided by an account of the Stone's recovery in 951 AD after it had been stolen 21 years earlier; according to a chronicler, the Stone was identified by its ability to float in water. If this account is accurate, it would rule out the Black Stone being an agate, basalt lava or stony meteorite, though it would be compatible with it being glass or pumice. It has been suggested that the Black Stone may be a glass fragment from the impact of a fragmented meteorite some 6,000 years ago at Wabar, a site in the Rub' al Khali desert some 1,100 km east of Mecca. The craters at Wabar are notable for the presence of blocks of silica glass, fused by the heat of the impact and impregnated by beads of nickel-iron alloy from the meteorite (most of which was destroyed in the impact). Some of the glass blocks are made of shiny black glass with a white or yellow interior and gas-filled hollows, which allow them to float on water. Although scientists did not become aware of the Wabar craters until 1932, they were located near a caravan route from Oman and were very likely known to the inhabitants of the desert. The wider area was certainly well-known; in ancient Arabic poetry, Wabar or Ubar (also known as "Iram of the Pillars") was the site of a fabulous city that was destroyed by fire from the heavens because of the wickedness of its king. If the estimated age of the crater is accurate, it would have been well within the period of human habitation in Arabia and the impact itself may have been witnessed.
