the Weekly World News, a satirical tabloid, which he described as an "unreliable source of data for discussing the origins of the South African spheres described as used by Forbidden Archeology". According to Cairncross, it appears that the source of the Weekly World News article is an earlier article by Barritt. This article appeared in a 1982 issue of Scope magazine about these objects. Additionally, Roelf Marx, as quoted in Cairncross and Pope and Cairncross, former curator of the Klerksdorp Museum, reports that he was misquoted regarding these objects. Marx was quoted in popular articles as saying that the objects rotated by themselves in vibration-free display cases in the Klerksdorp Museum. Instead, Marx stated that they rotated because of the numerous earth tremors generated by underground blasting in local gold mining. Similarly, inquiries of scientists, who studied these objects, have found that the claims that NASA found these objects to be either perfectly balanced, unnatural, or puzzling are unsubstantiated. Published descriptions of these spheres being harder than steel are definitively false in terms of Mohs scale of mineral hardness. Steel can vary from 4 to 8 on the Mohs scale, depending on the type of alloy, heat treatment, and whether it is case-hardened or not. An examination of several Klerksdorp spheres found none to be harder than 5.0 on the Mohs scale. For comparison, common glass has a Mohs hardness of 5.5. See also Geofact References Pseudoarchaeology North West (South African province) Spheres Geology of South Africa Geofacts