The origins of two purportedly pre-Columbian Mexican crystal skulls

The well-known life-size rock crystal skull in the British Museum was purchased in 1897 as an example of genuine pre-Columbian workmanship, but its authenticity has been the subject of increasing speculation since the 1930s. This paper is concerned with the history, technology and material of the skull and another larger white quartz skull, donated recently to the Smithsonian Institution. Manufacturing techniques were investigated, using scanning electron microscopy to examine tool marks on the artefacts, and compared with Mesoamerican material from secure contexts. A Mixtec rock crystal goblet and a group of Aztec/Mixtec rock crystal beads show no evidence of lapidary wheels. They were probably worked with stone and wood tools charged with abrasives, some of which may have been as hard as corundum. Textual evidence for Mexican lapidary techniques during the early colonial period, supported by limited archaeological evidence, also indicates a technology without the wheel, probably based on natural tool materials. In contrast, the two skulls under consideration were carved with rotary wheels. The British Museum skull was worked with hard abrasives such as corundum or diamond, whereas X-ray diffraction revealed traces of carborundum (SiC), a hard modern synthetic abrasive, on the Smithsonian skull. Investigation of fluid and solid inclusions in the quartz of the British Museum skull, using microscopy and Raman spectroscopy, shows that the material formed in a mesothermal metamorphic environment equivalent to greenschist facies. This suggests that the quartz was obtained from Brazil or Madagascar, areas far outside pre-Columbian trade networks. Recent archival research revealed that the British Museum skull was rejected as a modern artefact by the Museo Nacional de Mexico in 1885, when offered for sale by the collector and dealer, Eugène Boban. These findings led to the conclusion that the British Museum skull was worked in Europe during the nineteenth century. The Smithsonian Institution skull was probably manufactured shortly before it was bought in Mexico City in 1960; large blocks of white quartz would have been available from deposits in Mexico and the USA.     

A possible case of renal osteodystrophy in a skeleton from medieval Wharram Percy,England

The skeletal remains of a child aged 13–15 years, recovered from Wharram Percy, England, and dating from AD 960–1700, were examined using gross observation, radiography and scanning electron microscopy. Lesions suggestive of renal osteodystrophy were found. Palaeopathological recognition of renal disease has hitherto relied upon the identification of soft tissue lesions or the presence of urinary calculi. This appears to be the first palaeopathological identification of renal insufficiency on the basis of skeletal changes alone. Copyright © 2007 John Wiley & Sons, Ltd.     

Lapis lazuli usage for blue decoration of polychrome painted glazed pottery: a recurrent technology during the Middle Ages in Apulia (Southern Italy)

Seven fragments of atypical proto-majolica from the archaeological site of Siponto (Manfredonia, Foggia) were analysed by chemical and physical methods. All fragments have blue, brown and yellow painted decorations. Raman microscopy and Scanning Electron Microscopy–Energy Dispersed Spectroscopy (SEM–EDS) investigations identified the blue pigment to lapis lazuli. We previously identified this mineral in the blue coloration of the tin–lead glaze of proto-majolica finds at other Medieval sites in Apulia (Castel Fiorentino and Lucera). The discovery of the fragments from Siponto, in spite of their peculiar technological-decorative features, proves that the use of lapis lazuli as a ceramic pigment was not an isolated occurrence, but was quite common in the Middle Ages in the production of typologically heterogeneous ceramics in Southern Italy.     

Unveiling the Use of Creta in Roman Plasters: Analysis of Clay Wall Paintings From Brixia (Italy)

The paper describes the analysis of a particular kind of plaster from the walls of the Roman Sanctuary (first half of the first century bce ) in the centre of Brixia (now Brescia, Italy), which is an outstanding example of Roman Republican architecture. The walls were plastered and painted with different patterns, imitating marble panels and curtains. Optical microscopy on thin sections, X‐ray diffraction and infrared spectroscopy were performed on several samples of the plaster in order to reveal the execution technique. The palette consisted of glauconite, celadonite, Egyptian blue, and red and yellow ochres. In some cases, an organic compound, possibly a lipidic compound, was present in the external paint layer, as a surface treatment. The plaster contains two superimposed coats: the render coat with lime binder and sandy aggregate; the finish coat with a clay fraction (illite, chlorite, kaolinite), together with calcite from slaked lime and grains of quartz, silicate and carbonate rocks. Although Vitrivius' De architectura reported the use of creta (clay) as daub smeared on reed vaults, the Sanctuary of Brixia represents the first documented use in Roman buildings in a painted plaster laid on a stone masonry wall.     

Persistence of birefringence and specific collagen cross-links in dentine of teeth of the ‘Nuraghi’ population living in Sardinia BC 1500–1200

Well preserved bones of the Nuraghi population, discovered in 1980, are deposited in the Department of Biomedical Sciences, Division of Human Anatomy of the University of Sassari, in Sardinia, Italy. The Giant Tomb belongs to the megalithic monuments constructed in the period BC 1500–1200. The origin, history and the fate of Nuraghi population is not well known. Many cone-shaped fortresses are found in Sicily and megalithic monuments for burial purposes were built in their proximity. Due to the good macroscopic preservation of the mineralized parts of the Nuraghi skeletons we decided to compare the histological and biochemical structure of the recovered Nuraghi teeth with contemporary ones. Crown dentine of four Nuraghi molar and four premolar teeth were analysed and compared with contemporary molars and premolars removed for orthodontic reasons from 17–40-year-old patients in the Dental School, University of North Carolina at Chapel Hill USA. Evaluation of the collagen cross-links of dentine collagen was performed using a HPLC technique to analyze for hydrolysates. Nonreducible, stable cross-links pyridinoline and its lysyl analogue were quantified by fluorescence (excitation 330 nm, emission 390 nm). The concentration of reducible, labile cross-links referred to as DHLNL and HLNL (dehydro-dihydroxylisinorleucine) were identified and calculated by chromatography after the application of NaB³H₄ with integration of respective peaks and converting the numbers into a residue per mole of collagen basis. The ultrastructure of collagen was estimated by its persistent birefringence in polarized light after staining with Picrosirus Red. It was found that dentine collagen of Nuraghi teeth resisted environmental factors sufficiently well to preserve the molecular ultrastructure of collagen fibres, proved by their birefringence and by the preservation of some of the stable and reducible collagen cross-links, characteristic for skeletal tissues. © 1998 John Wiley & Sons, Ltd.     

Scanning electron microscopy of dry hide working tools: The role of abrasives and humidity in microwear polish formation

This paper presents the results of the scanning electron microscopy of a series of experimental tools designed to investigate the role of abrasive agents and humidity in microwear polish formation. The tools—35 end scrapers—were divided into four groups and used to work dry hide. It was found that both humidity and abrasive agents are two basic variables in the development of the microwear polish.     

Investigation of chemical changes in bone material from South African fossil hominid deposits

The bone fragments of the Australopithecus Africanus from the dolomitic cave in the Cradle of Humankind in South Africa have been studied by the use of several spectral techniques. The aim was to establish their degree of preservation and possibilities of inferring the life conditions from them. X-ray diffraction studies revealed the transformation of the mineral components partially into fluoroapatite form with addition of goethite, birnessite and quartz phases and with surprisingly well preserved collagen remains. Several important chemical elements were detected by using the electron (EPMA) and synchrotron-based X-ray fluorescence (XRF) microprobes. Among them, Sr and Zn were distributed in a way following the distribution of Ca, the main element of the bones. We suspect the immanent crystallographic substitution of Ca in this case in native bone. Iron followed the distribution of Sr but while Sr is distributed in a continuous way in more rigid locations, iron occurs mainly in the edge zones of the bones and in spot-like inclusions inside. Some part of the spots located in a very edge of bone is also filled with Mn and Cu. It suggests that the porosity and fracture of bones plays a more significant role in the localization of Fe, Mn and Cu. They also form a rigid thin layer (100–250 μm) avoiding further penetration. As (as AsO₄³⁻?) distribution pattern is unique and seems to occur in those locations where the concentrations of Sr are small. The conditions for bone penetration as determined from Eh-pH diagrams suggest that is rather impossible to preserve the organic matter in locations of Mn and also that Mn and Fe hardly can meet in the same spots.     

Tracing firing technology through clay properties in Cuzco,Peru

The purpose of this study was to identify changes in firing practices that occurred during a timeframe that saw the introduction of European kiln technology to the Andes (AD 900–1800). Pottery from an excavated context at the archaeological site of Aqnapampa in the southern highlands of Peru was examined for changes in paste recipes that adapted local materials to increased firing temperatures indicative of evolving firing technologies. Sherds (60) and fragments refired to 890 °C from 12 stratigraphic levels were compared by style, surface treatment, paste color, and vitrification structures (ESEM). Four technological phases of the Cuzco pottery sequence emerged and were used to evaluate the trajectory of a single decorative style (Killke). Previously thought to have been produced in pre-Inca times and curated into later periods, the Killke sherds presented evidence that the style was produced using technologies introduced in the Inca and Spanish Colonial Period.     

Burned bone in the Howieson’s Poort and post-Howieson’s Poort Middle Stone Age deposits at Sibudu (South Africa): behavioral and taphonomic implications

Despite a growing awareness of the wide range of information that can be provided by detailed analyses of burned bone from archaeological contexts, such analyses are still relatively uncommon. This paper focuses on the behavioral and taphonomic implications of burned bone from the Middle Stone Age (MSA) site of Sibudu Cave (South Africa), reporting on the analysis of a large sample (>377,000 fragments) of bone recovered from the Howieson’s Poort (HP) and post-HP MSA deposits at the site. Faunal remains were initially sorted into burning categories based on changes in color; microscopic analyses focused on the optical properties of the bone matrix (degree of preservation of the bone structure, reflectance and fluorescence) indicated that the color is a valid indicator of thermally altered bone in the Sibudu assemblage. The association of burned bone with hearths, the intensity of burning damage, and the sheer quantity of thermally altered bone suggests that the bone was not burned primarily as a result of natural fires. We propose that the high incidence of burned bone primarily reflects two types of site maintenance activities: first, the discarding of bone into fire as a means of disposing of food waste (as also argued by Cain [2005, Using burned animal bone to look at Middle Stone Age occupation and behavior. J. Archaeol. Sci. 32, 873–884], for a smaller sample of material from the post-HP and late MSA deposits at the site), and second, the incidental burning of bone on/near the surface during the periodic burning of plant-based bedding. In considering the taphonomic implications of the burned bone, we demonstrate that calcined bone is in fact more heavily fragmented than unburnt or moderately burned bone. Furthermore, cortical preservation was negatively correlated with the intensity of burning damage, which has implications for the study of surface modifications. These results indicate the importance of conducting thorough taphonomic analyses prior to making comparisons between units that show differing degrees or intensities of burning damage.     

甘肃玉门火烧沟遗址出土红-黄色混合颜料的再分析

古代颜料的科学分析一直是考古学研究和艺术史研究的重要内容,分析和确定颜料的矿物成分,对于中国古代科技史研究具有很重要的意义。本工作利用扫描电子显微镜和激光拉曼显微镜对玉门火烧沟遗址出土的红黄色颜料进行了分析,确定了红黄色混合颜料是雄黄、拟雄黄、三氧化二砷、硫磺与石膏的混合物。