J. Wadsworth, D.R. Lesuer /Materials Characterization 45(2000) 289-313 And, most importantly, they also concluded Herbert Hoover (1928-1932), was a mining and metallurgical engineer (Stanford University, 1896) Furthermore, the metallurgical evidence supports the archaeological evidence, which suggests that the who became a famous and wealthy engineer before entering the political scene. He and his that structure was being bui wife translated the famous text de re metallica by Agricola, from the Latin to the English in 1912 Although accounts by the excavation teams em- [6, p. 421]. In that book, he footnoted his phasize the fact that the plate was found within the thoughts on the history of iron in Agricolas pyramid, and is therefore contemporaneous with the section on iron making. He considered that the amid. this view has not been generally a beginning of the Iron Age was in the prehistory period, that the egyptians knew iron 5000 to 6000 Subsequent to the paper by El Gayer and Jones, years ago, and used iron tools to carve the stones the only other investigation of the plate came in of the great pyramids. Thus, if the iron plate of 1993 by Craddock and Lang [5]. They agreed with Gizeh could be accurately dated, it would be a he El Gayer and Jones study that the structure was significant point in determining the evolution of similar to banded, wrought iron consisting of areas large, man-made, iron-based artifacts of varying carbon content. However, the absence o In order to resolve the issue of the date of the slag stringers and the presence of very large num- plate, it is possible to turn toC dating. Using this bers of other inclusions, containing unusually high technique, the dating of ancient steels has in fact levels of Ca and P, led Craddock and Lang to a been done successfully. In the last decade in parti- quite different conclusion regarding the method o cular, carbon dating on relati manufacture(and therefore the origin and likely weighing as little as a fraction of a gram to several age)of the plate. They believe the structure to be grams, has been accomplished by using accelerator one derived from "cast iron smelted with charcoal and then treated by the finery process to remove the carbon and produce a solid lump or bloom of wrought iron. "They go on to cite work proposing that this technique was the usual method of making iron in the post-medieval Islamic world. The Gizeh plate remains unusual, even in this scenario, be- ause of the very high level of inclusions that it contains. Craddock and Lang do not. on the basis of their 1993 analysis, believe the plate is con- temporaneous with the pyramid, concluding that: the plate of iron from the Great Pyramid is of no great antiquity. Nonetheless, these authors confirm that if its age were to be contemporaneous with the d that it would be the earliest substantial piece of iron known, a finding accepted by the famous scientist Petrie in 1883 Given these controversial and competing views, it is worth emphasizing the importance of the late of the plate. It is generally accepted that iron and steel were not made in this quantity until about 1500 BC. Certainly, examples exist in that me frame. some of them fame example, daggers of both gold and iron were found on Tutankhamun's mummy (Fig. 1)which known to be from 1350 BC. There are occasional claims that older pieces exist; for example, it is claimed that an iron knife blade in a museum in Turkey is from 2500 BC, but there is no supportin Fig. 1. Evidence of steel from 1350 BC. Daggers of iron and Nonetheless, some significant authors have pro- gold from Tutankhamun's grave, and their sheaths. Insert: posed a much older start to the Iron Age. For Position of iron dagger on Tutankhamun's mummy(after example, a former president of the United States, Sherby [7DAnd, most importantly, they also concluded: Furthermore, the metallurgical evidence supports the archaeological evidence, which suggests that the plate was incorporated within the pyramid at the time that structure was being built. Although accounts by the excavation teams em￾phasize the fact that the plate was found within the pyramid, and is therefore contemporaneous with the pyramid, this view has not been generally accepted by archeologists. Subsequent to the paper by El Gayer and Jones, the only other investigation of the plate came in 1993 by Craddock and Lang [5]. They agreed with the El Gayer and Jones study that the structure was similar to banded, wrought iron consisting of areas of varying carbon content. However, the absence of slag stringers and the presence of very large num￾bers of other inclusions, containing unusually high levels of Ca and P, led Craddock and Lang to a quite different conclusion regarding the method of manufacture (and therefore the origin and likely age) of the plate. They believe the structure to be one derived from ``cast iron smelted with charcoal, and then treated by the finery process to remove the carbon and produce a solid lump or bloom of wrought iron.'' They go on to cite work proposing that this technique was the usual method of making iron in the post-medieval Islamic world. The Gizeh plate remains unusual, even in this scenario, be￾cause of the very high level of inclusions that it contains. Craddock and Lang do not, on the basis of their 1993 analysis, believe the plate is con￾temporaneous with the pyramid, concluding that: ``the plate of iron from the Great Pyramid is of no great antiquity.'' Nonetheless, these authors confirm that if its age were to be contemporaneous with the pyramid that it would be ``the earliest substantial piece of iron known,'' a finding accepted by the famous scientist Petrie in 1883. Given these controversial and competing views, it is worth emphasizing the importance of the date of the plate. It is generally accepted that iron and steel were not made in this quantity until about 1500 BC. Certainly, examples exist in that time frame, some of them famous ones. For example, daggers of both gold and iron were found on Tutankhamun's mummy (Fig. 1) which is known to be from 1350 BC. There are occasional claims that older pieces exist; for example, it is claimed that an iron knife blade in a museum in Turkey is from 2500 BC, but there is no supporting evidence presented. Nonetheless, some significant authors have pro￾posed a much older start to the Iron Age. For example, a former president of the United States, Herbert Hoover (1928 ± 1932), was a mining and metallurgical engineer (Stanford University, 1896), who became a famous and wealthy engineer before entering the political scene. He and his wife translated the famous text De Re Metallica by Agricola, from the Latin to the English in 1912 [6, p. 421]. In that book, he footnoted his thoughts on the history of iron in Agricola's section on iron making. He considered that the beginning of the Iron Age was in the prehistory period, that the Egyptians knew iron 5000 to 6000 years ago, and used iron tools to carve the stones of the great pyramids. Thus, if the iron plate of Gizeh could be accurately dated, it would be a significant point in determining the evolution of large, man-made, iron-based artifacts. In order to resolve the issue of the date of the plate, it is possible to turn to 14C dating. Using this technique, the dating of ancient steels has in fact been done successfully. In the last decade in parti￾cular, carbon dating on relatively small samples, weighing as little as a fraction of a gram to several grams, has been accomplished by using accelerator Fig. 1. Evidence of steel from 1350 BC. Daggers of iron and gold from Tutankhamun's grave, and their sheaths. Insert: Position of iron dagger on Tutankhamun's mummy (after Sherby [7]). J. Wadsworth, D.R. Lesuer / Materials Characterization 45 (2000) 289±313 291