Forbidden Archeology_ The Full Unabridged Edition - Michael A. Cremo [362]
If the skull fragments were native to the Piltdown gravels and were not artificially stained as suggested by Weiner and his associates, then how is one to explain the gypsum (calcium sulfate) in the skull fragments? One possibility is that Dawson used sulfate compounds (along with or in addition to potassium dichromate) while chemically treating the bones to harden them after their excavation, thus converting part of the bones’ hydroxy-apatite into gypsum.
Another option is that the gypsum accumulated while the skull was still in the Piltdown gravels. The British Museum scientists claimed that the concentration of sulfates at Piltdown was too low for this to have happened. But Bowden (1977, p. 15) observed that sulfates were present in the area’s groundwater at 63 parts per million and that the Piltdown gravel had a sulfate content of 3.9 milligrams per 100 grams. Admitting these concentrations were not high, Bowden said they could have been considerably higher in the past. We note that Oakley appealed to higher past concentrations of fluorine in groundwater to explain an abnormally high fluorine content for the Castenedolo bones (Appendix 1).
Significantly, the Piltdown jaw contained no gypsum. The fact that gypsum is present in all of the skull fragments but not in the jaw is consistent with the hypothesis that the skull fragments were originally from the Piltdown gravel while the jaw was not.
Chromium was present in the five skull fragments found by Dawson alone, before he was joined by Woodward. This can be explained by the known fact that Dawson dipped the fragments in potassium dichromate to harden them after they were excavated. The additional skull fragments found by Dawson and Woodward together did not contain any chromium.
The jaw did have chromium, apparently resulting from an iron-staining technique involving the use of an iron compound and potassium dichromate.
To summarize, it may be that the skull was native to the Piltdown gravels and became thoroughly impregnated with iron over the course of a long period of time. During this same period of time, some of the calcium phosphate in the bone was transformed into calcium sulfate (gypsum) by the action of sulfates in the gravel and groundwater. Some of the skull fragments were later soaked by Dawson in potassium dichromate. This would account for the presence in them of chromium. The fragments found later by Dawson and Woodward together were not soaked in potassium dichromate and hence had no chromium in them. The jaw, on the other hand, was artificially iron-stained, resulting in only a superficial coloration. The staining technique involved the use of a chromium compound, which accounts for the presence of chromium in the jaw, but the staining technique did not produce any gypsum.
Alternatively, if one accepts that the iron-staining of the skull fragments (as well as the jaw) was accomplished by forgery, then one has to assume that the forger used three different staining techniques: (1) According to the British Museum scientists, the primary staining technique involved the use of an iron sulfate solution with potassium dichromate as an oxidizer, yielding gypsum (calcium sulfate) as a byproduct. This would account for the presence of gypsum and chromium in the five iron-stained skull fragments first found by Dawson. (2) The four skull fragments found by Dawson and Woodward together contained gypsum but no chromium (Weiner et al. 1955,