Kaaba stone: Not a meteorite, probably an agate

Kaaba stone, Not a meteorite, probably an agate, by Robert S. Dietz and John McHone, published in Meteoritics by the Meteoritical Society in 1974, is a peer reviewed geological note arguing, on the basis of diffusion banding visible in photographs and descriptions of the Black Stone's structure, that it is most likely an agate rather than a meteorite, the more popularly assumed origin. Its strength is that it is a specialist peer reviewed argument grounded in actual meteoritic science, from scientists whose expertise is identifying meteorite material specifically, rather than a general assumption repeated without geological examination. Its limit is that the stone itself has never been available for direct laboratory sampling by outside scientists, so any geological argument, including this one, works from external observation and photographic evidence rather than the hands-on testing a definitive identification would require, and this remains one contribution to an active, still not fully settled scientific debate over the stone's origin.