Heinrich noted that even fluted balls are not ideal balls and some are made of fused balls. Heinrich  states that one of Michael Cremo's resources on the supposedly abnormal realms was the Weekly World News, a satellite boulevard newspaper which he described as "an untrustworthy resource for the discussion about the origin of the southern Africa realms described by Prohibited Archaeology".
Like Cairncross notes, it seems that the Weekly World News item is a previous Barritt article This article was published in a 1982 edition of Scope Review about these Items. Like the Weekly World News, Scope was a southafrican tobacco magazin which cannot be considered a reliable well.
Descriptions  of these balls, which are hard as iron, are irrelevant to the Mohs range of minerals used. Steels can range from 4 to 8 on the Mohs range, dependent on the kind of alloys, the thermal treatments and whether or not it is case-hardened. A study of several Klerksdorp balls showed that none is more than 5.0 on the Mohs scale For comparison: ordinary jar has a Mohs temper of 5.5.
Leap to the top: a d e f f g e f gh hij k m m n Heinrich, P.V., 2007, Südafrikanische Konkremente der Kontroverse: Vol. 39, Number One, pp. 7-11. Skip up to: a d e f g e f g e g p k 1 mn p Heinrich, P.V., 2008, The mysterious "Spheres" of Ottosdal, Southafrika.
South Africa Geological Survey Bulletin No. 8. A new horizon for Wonderstone, Mining Weekly, December 3, 2004. Leap up ^ Heinrich, P.V. 1996. South African deep-ball conflict: