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Discovery of pigments at Middle Palaeolithic sites is of interest in the context of the ongoing debate about the tempo and mode of the emergence of modern human behaviour. Here we analyse four previously undescribed fragments of pigmental material from Es-Skhul shelter, layer B, Israel, McCown excavations, identified at the Department of Palaeontology, Natural History Museum, London. One of them is still partially embedded in the hard breccia characteristic of this layer. Inspection of breccia fragments from layer B has led to the identification of small pieces of red and orange pigmental material still enclosed in large clasts, further corroborating the attribution of the larger pieces analysed in this study to layer B. The four objects are studied using optical microscopy, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Energy Dispersive X-ray (EDX), X-ray micro-diffraction (μ-XRD), Particle-Induced X-Ray Emission Spectrometry (PIXE), and Proton-Induced Gamma-ray Emission (PIGE). The specimens display various hues of yellow, orange, red, and one of them presents a gradual variation of shade from yellow to dark orange. SEM/EDX analysis identifies two specimens (Skhul 1 and 2) as being composed of iron-rich calcium phosphate, the third (Skhul 3) of potassium-rich clay with titanium-rich iron oxide inclusions, and the fourth (Skhul 4) of pure iron oxide crystals. TEM/EDX and μ-XRD analysis demonstrate that three pieces (Skhul 1, 2 and 4) were heated to at least 300 °C, a process that has partially or completely dehydrated goethite into haematite and changed their pristine yellow colour into orange or red. Skhul 3 shows no sign of heating, suggesting that its haematite content has a geological origin. The different mineral composition of the pieces suggests that they must come from a variety of sources. This implies that the associated collection strategies included the selection of materials that differed not only with respect to colour but also with respect to other physical and chemical properties. Although no formal proof exists that these lumps of pigmental material were deliberately heated, results obtained are consistent with this explanation.

Recent research conducted on the Laikipia Plateau in Kenya highlighted several shortfalls in the existing models for understanding and interpreting past iron production technologies. The research was undertaken in order to assess variability in past pastoralist iron production techniques – the first such archaeometallurgical exploration in the region. In all, seven furnaces and one iron production refuse area were excavated across two discrete sites separated by only 3 km: Mili Sita and Cattle Dip, both dating to the second half of the second millennium AD. The recovered archaeometallurgical materials – slag, furnace wall, and tuyeres – were analysed using a combination of optical microscopy, SEM-EDS and ED-XRF. The results revealed that the technologies in question were complex and sophisticated, and their reconstruction and interpretation required some special considerations. The exploitation of titania-rich black sand was observed to bear a major influence on the resulting slag compositions at both sites, and use of these specific materials resulted in consistently efficient smelting episodes, demonstrating the technical competence and skill of the past smelters. However, although the slag compositions and microstructures of all the samples were markedly similar between the two sites, striking stylistic variation was apparent in the furnace design. This raised questions not only about the organisation and identity of the smelters who were working in this area at this time, but also of the reliability of assuming that similar slag compositions – peculiar as these might be – reflect similar technological (or sociotechnical) systems (cf. Pfaffenberger, 1992 ). A further problem encountered was that the consequently ulvite-rich slag was comprised of five, not three, major constituents – titania and lime in addition to iron oxide, alumina and silica. This meant that the operating parameters of these smelting episodes could not be easily interpreted using the usual models, which tend to be based around the assumption of fayalitic slag. As such, this paper will discuss to what extent consistency in technological style, in a broad, sociocultural sense, can be inferred through slag analysis, as well as the need for the formulation of wider reaching models that encompass the full scope of technical variation in iron production.

Some Neolithic ceramics from south-eastern Spain have red to brown external decorations called “almagras” (red ochre). The pigment layer is essentially composed of a mixture of clay and iron oxides: haematite (red) and maghemite (brown). It is suggested that maghemite was formed during the firing process of ceramic in a reducing atmosphere. Several laboratory tests have been carried out to obtain maghemite by adding charcoal or pinewood sawdust to similar ceramic pastes. In fact, maghemite was formed, even when the piece was simply covered with pinewood sawdust before firing. The diverse original red colours are due to variations in iron oxide (or calcite) content and to redox conditions in the firing procedure. Brown- coloured ceramics owe their colour to maghemite and must be considered as a “fabrication defect”, due to the position of the ceramic piece in a zone where a reducing atmosphere prevailed in the course of firing.