The Wonderstone spheres. One of the Wonderstone (Ottosdal or Klerksdorp) spheres In the Wonderstone Mines at Ottosdal (West Transvaal, South Africa), hundreds of metallic spheres have been found over several decades in pyrophillite (or wonderstone) deposits of Precambrian date, some 2.8 billion years old. Pyrophillite is a metamorphosed sedimentary mineral mined for use in masonry buildings, as an absorbent, as a filler, as an ingredient in industrial compounds and for a variety of other uses. Two types of sphere are alleged to have been found in the pyrophillite; one is a bluish metal with white inclusions, while the other has a metallic coating around a spongy material. Only examples of the second type seem to have been examined by geologists, who have found that they consist of pyrites and goethite.
The first report citing these spheres has been traced to The Weekly World News , 27 July 1982. You can find more dismantlings of the claims here, by Tim McGuinness and here, by Paul V Heinrich . Klerksdorp spheres. UFO Sphere Shocks Brazil. Betz Mystery Sphere. Venezuela. Chartage. BALTIC SEA, Russia. Costa Rica. Bosnia. China. 'Space Ball' drops on Namibia. Spheres - Easter Island. Spheres -New Zealand.