Klerksdorp spheres are small objects, often spherical to disc-shaped, that have been collected by miners and rockhounds from 3-billion-year-old pyrophyllite deposits mined by Wonderstone Ltd., near Ottosdal, South Africa. They have been cited by pseudoscientists and reporters in books, popular articles, and many web pages as inexplicable out-of-place artifacts that could only have been manufactured by intelligent beings. Geologists who have studied these objects have concluded that the objects are not manufactured, but are rather the result of natural processes. Description The Klerksdorp spheres typically range in diameter from . As illustrated by geologist Paul Heinrich, they vary widely in shape from either approximate or flattened spheres to well-defined discs and often are intergrown. Petrographic and X-ray diffraction analyses of specimens of these objects found that they consist either of hematite (Fe2O3) or wollastonite (CaSiO3) mixed with minor amounts of hematite and goethite (FeOOH). Observations by Bruce Cairncross, Louis Taylor Nel and others indicated that many of the Klerksdorp spheres found in unaltered pyrophyllite consist of pyrite (FeS2). The color of the specimens studied by Paul Heinrich ranged from dark reddish brown, red, to dusky red. The color of those objects composed of pyrite is not known. All of the specimens of these objects, which were cut open by Heinrich, exhibited an extremely well-defined radial structure terminating on either the center or centers of a Klerksdorp sphere. Some of these objects exhibit well-defined and parallel latitudinal grooves or ridges. Even specimens consisting of intergrown flattened spheres exhibit such grooves. Geological explanation of their origin Various professional geologists agree that the Klerksdorp spheres originated as concretions, which formed in volcanic sediments, ash, or both, after they accumulated 3 billion years ago. Heinrich argues that the wollastonite nodules formed by the metamorphism of carbonate concretions in the presence of silica-rich fluids generated during the metamorphism of the volcanic deposits containing them into pyrophyllite. It was also argued that the hematite nodules represent pyrite concretions oxidized by weathering of near surface pyrophyllite deposits. Below the near-surface zone of weathering, which has developed in the pyrophyllite, pyrite concretions are unaffected by weathering and, thus, have not been altered to hematite. The radial internal structure of these objects is a pseudomorph after the original crystalline structure of the original carbonate or pyrite concretion. Both Cairncross and Heinrich argue that the grooves exhibited by these concretions are natural in origin. As proposed by Cairncross, the grooves