Petrologic Study of Amarna Sculptures in the Collection of M. A. Mansoor Sons
Robert R. Compton
This report describes a study of thirteen limestone sculptures from Amarna which are now in the collection of M. A. Mansoor Sons. The purpose of this work was to determine as far as possible if these pieces are of ancient manufacture, or if they are forgeries, and this question has risen in part because an earlier report ( dated April 14,1949 ) suggested that the pieces are of " fairly modern origin ". I have read this report as well as a somewhat later and more thorough study (dated 28-11- 1950 ), and I will comment on these reports after describing my own study of the sculptures.
The thirteen pieces I studied may be classified as follows:
The descriptions in the other two reports leave little doubt that most of the other pieces in the originally large collection are similar in technical aspect to the ones studied here.
All of the pieces are of rather fine-grained foraminiferal limestone. This stone is pink to dull red in all the pieces except number 183 and the large bust, which are pale grayish yellow. Except for the color difference, the stone of the pieces is essentially identical, and almost certainly came from the same deposit. One of the most notable features of the stone is the presence of lensoid to irregular bodies of nearly white material which looks like clay to the unaided eye, but which was found to be chalky limestone with less foraminiferal debris than the main body of the rock, and without the red and yellow iron oxide pigments which occur elsewhere in the rock. These white bodies are aligned with what was probably the original bedding of the deposit. They were unquestionably formed at the same time as the rest of the stone, and were not applied later.
Most of the foraminifera are large enough ( 0.5 to 3.0 mm. ) to be seen readily with the unaided eye, for the matrix around them has been etched away and the fossils stand out in clear relief. Here and there a small fish bone can be seen. These various fossil forms, the white patches, and the manner in which all of these things are distributed in the rock prove without question that the stone is natural, not paste.
The nature of the weathering on the surface of the pieces is of greatest importance in proving that the sculptures are ancient. With the exception of a few fresh breaks, all of the surfaces are weathered to some degree, and, in a general sense, the pieces are all weathered about equally. The principal effect of weathering has been an etching away of the matrix around the foraminifera shells so that the fossils stand out 0.1 to 0.5 mm. above the present level of matrix. It is important to note that the surfaces of the foraminifera themselves are not etched, but rather are generally polished. In some cases, they are covered by a thin pearly patina, and although this patina proved too thin to test positively, most appears to be calcium carbonate and some may be opaline silica.
Besides the foraminifera, all pieces show at least a few irregular bodies of brown limonite (hydrated ferric oxides ) and of black manganese oxides. These bodies are etched into relief, and generally have highly polished rounded upper surfaces ( see especially pieces 137, 257, 244, and large bust ). Many of the manganese oxide bodies show the intricately branching forms called dendrites;. these are especially common in the large yellow bust. I cut into both limonite and manganese oxide bodies on several of the pieces ( 137, 257, and the large bust ) and although they were found to extend for more than a millimeter into the stone ( deeper cutting was thought undesirable ), they are enlarged at the surface, as though they had received an additional patina during weathering. Some of these dark shiny bodies stand about 0.5 mm. above the etched surface of the limestone.
Other effects of weathering and aging include the presence of brown stains and deposits, and the darker pigmentation of the surfaces, especially the edges, of the pieces. I could not determine the nature of the brown stains with certainty. Some may well be animal excretions, as suggested in the report dated 28-11- 1950. The darkening of the surfaces is caused in part by dirt rubbed on during handling and in part by a greater concentration of iron oxide pigments near the surface of the pieces. This increased pigmentation is not a patina ( which is a layer deposited on the surface ), and I can think of no way in which it could be produced synthetically in a comparatively short time.
It is notable that the degree of etching and the other effects of weathering are irregularly distributed on the pieces, as though parts of the objects were from time to time more exposed than other parts. Piece 137 shows especially clearly the unequal patchy etching that would be expected from natural weathering. The white bodies in the limestone, which are softer than the rest, are generally more deeply etched, and head number 130 has deeply weathered pits on the top and left side, which apparently formed where pyritic patches in the limestone produced rapid weathering. It is exceedingly doubtful that such natural appearing patterns could have been achieved by a forger.
In order to make certain that the weathering on the pieces could not be produced by synthetic etching, I carefully etched two fresh cuts on the bases of piece 235 and the large bust, by repeated applications of very dilute hydrochloric acid. The colors produced were bright orange on the pink limestone and bright orange-yellow on the yellow limestone, and these are very different colors from those on the natural surfaces. More important than this discoloration, however, is the fact that the synthetically etched surface has an entirely different configuration than the rest of the pieces. As has been noted above, natural weathering removed the more porous matrix and left the perfectly preserved foraminifera standing in relief ; the synthetic etching, however, cut into foraminifera and matrix to exactly the same degree, producing an intricately pitted and honeycombed surface. No surface in any way resembling this was seen on the pieces. It is concluded that the weathering of the pieces is natural, and consisted of very slow hydration and disaggregation of the more porous matrix. This is essentially a mechanical weathering, and would be expected to take place where the air contained very little water and carbon dioxide. Such conditions must certainly have held in Egypt, especially where the objects were buried in dry silt and sand, as appears to have been the case here.
The breaks on the pieces range from a few that are modern and unweathered to breaks with various degrees of weathering. However, just because many of the breaks are much weathered, does not mean they were made at the time the pieces were carved. Partial destruction of the pieces ( originally complete statues ? ) could have taken place as much as several hundreds of years after their manufacture and still given time for the weathering seen. This is because the rate of weathering was very slow. In any case, I suggest that the fact that the breaks are not equally weathered is in itself strong evidence for the authenticity of the pieces.
Finally, with regard to the two reports already made on the Mansoor collection, that one dated 28-11-1950 seems to me to be well founded petrologically. It covers many items that only someone with a knowledge of Egyptology could present, and I note that this report concludes that the pieces are authentic. The report dated April 14,1949, is based mainly on petrologic and mineralogic points, and I feel that most of these are weak, to say the least. As far as I can see, the fluorescence tests offer nothing to indicate the pieces are not old, nor does the author state just what is the " false condition " he refers to. His comments on his microscopic examinations, too, offer nothing tangible to cause question of the age and authenticity of the pieces, yet he somehow concludes that the pieces are " of fairly modern origin ". Perhaps his error has been in comparing these pieces with ancient pieces that were weathered under different conditions --probably mainly exposed at the surface; however, it is impossible to judge his conclusions critically since he offers little evidence of how he arrived at them.
My conclusions may be summarized as follows :
Robert R. Compton
Stanford University
Stanford, California
December 18,1958