The Black Stone of the Kaaba

The most famous sacred meteorite is the Black Stone of the Kaaba. The Kaaba is a cubical building in Mecca toward which Moslems pray five times daily. The Black Stone, set in the northeastern outside corner of the Kaaba, is considered to be the most sacred treasure of Islam.

The Kaaba also served as a center of worship for pre-Islamic Arabs and was reputed to contain 360 idols. In 630 the triumphant prophet Mohammed returned to Mecca and cleansed the temple of the idols after honoring the Black Stone. The heretical Qarmatian sect stole the stone in 930, but it was recovered 21 years later with positive identification provided by the stone's ability to float on water. In 1050 a mad Egyptian caliph sent a man to destroy the relic. The Kaaba was twice burned down and was flooded in 1626. During these trials the original stone was broken up into about 15 pieces. It was finally set in cement surrounded by a silver frame.

Islamic tradition variously describes the stone as coming from heaven and as originally hyacinth in color before it turned black because of humanity's sins. Reports of its visual appearance mention a dark, reddish black color, smooth surface, some apparent banding, and small crystal inclusions. Although generally regarded as a meteorite, it cannot be an iron-type meteorite since it fractures, nor can it be a stony meteorite since it would not have withstood the handling and would sink in water. Similar arguments may reject nonmeteoritic origins, such as basalt or agate.

In 1980 Elsebeth Thomsen proposed that the Black Stone is an impactite (fused sand mixed with meteoric material) from the Wabar Crater in Saudi Arabia's Empty Quarter (Sky & Telescope: November 1997, page 44). The Wabar impactite is a hard glass (so it is tough enough for repeated fondling yet can shatter) with a porous structure (so it can float) and having inclusions of white glass (the crystals) and sandstone (the banding). The change from its original lighter color could be due to the accumulated oils from frequent kissing and handling. A critical problem confronting this proposal is that several measurements suggest the Wabar Crater is only a few centuries old, though other analyses suggest it was formed 6,400 years ± 2,500 years ago. Whether or not Wabar is the source, the Black Stone still fits well with a desert impactite and a meteor tradition.