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Background Post-menopausal osteoporosis is a common health problem worldwide, most commonly caused by estrogen deficiency. Most of the information regarding the skeletal effects of this disease relates to trabecular bone, while cortical bone is less studied. The purpose of this study was to evaluate the influence of estrogen deficiency on the structure and mechanical properties of cortical bone. Methods Eight ovariectomized (OVH) and eight intact (control) Sprague Dawley rats were used.Structural features of femoral cortical bone were studied by light microscopy, scanning electron microscopy and synchrotron-based microcomputer-tomography and their mechanical properties determined by nano-indentation. Results Cortical bone of both study groups contains two distinct regions: organized circumferential lamellae and disordered bone with highly mineralized cartilaginous islands. Lacunar volume was lower in the OVH group both in the lamellar and disorganized regions (182 ± 75 µm3 vs 232 ± 106 µm3, P 3 vs. 247 ± 106 µm3, P 3 lacunae/mm3 vs. 47 ± 9×103 lacunae/mm3 in the lamellar region, P = 0.003 and 63 ± 18×103lacunae/mm3 vs. 75 ± 13×103 lacunae/mm3 in the disorganized region, P P Discussion Changes to cortical bone associated with estrogen deficiency in rats require high-resolution methods for detection. Caution is required in the application of these results to humans due to major structural differences between human and rat bone.

Manot Cave contains important human fossils and archaeological assemblages related to the origin and dispersal of anatomically modern humans and the Upper Paleolithic period. This record is divided between an elevated in situ occupation area and a connecting talus. We, thus, investigated the interplay between the accumulation of the sediments and their associated artifacts in the occupation areas and the translocation of part of these sediments and artifacts down the talus. We examined the lithostratigraphy of two excavation locations in the occupation area (areas E and I), and two in the talus (areas C and D). We also assessed the diagenetic processes that have affected all these areas. A linear array of stalagmites and stalactites separates the occupation area from the talus, demarcating a major topographic barrier between the two. We infer that during human occupation, sediment accumulation of soil, wood ash, and bone was rapid and that some sediments with their associated artifacts overflowed the barrier and translocated down the talus. During periods of nonoccupation, the ash in the occupation area partially dissolved owing to the release of acid from the degrading bat and bird guano, and the layer thicknesses decreased. The south side of the talus (area C) has a normally stratified archaeological record, with the older archaeological materials underlying the younger materials. This suggests that the barrier between the occupation area and area C was relatively shallow and allowed a fairly continuous sediment accumulation in the talus. In the central part of the talus (area D), the stratigraphy is complex and shows mixing, presumably owing to the steep underlying bedrock topography and the mixing that occurs when sediments move down a steep slope. Finally, the distribution of secondary phosphates is consistent with the location of a main cave entrance to the south of the Paleolithic occupation area.

Guanine crystals are widely used in nature as components of multilayer reflectors. Guanine-based reflective systems found in the copepod cuticle and in the mirror of the scallop eye are unique in that the multilayered reflectors are tiled to form a contiguous packed array. In the copepod cuticle, hexagonal crystals are closely packed to produce brilliant colors. In the scallop eye, square crystals are tiled to obtain an image-forming reflecting mirror. The tiles are about 1 μm in size and 70 nm thick. According to analysis of their electron diffraction patterns, the hexagon and square tiles are not single crystals. Rather, each tile type is a composite of what appears to be three crystalline domains differently oriented and stacked onto one another, achieved through a twice-repeated twinning about their ⟨011⟩ and ⟨021⟩ crystal axes, respectively. By these means, the monoclinic guanine crystal mimics higher symmetry hexagonal and tetragonal structures to achieve unique morphologies.

Brushite, CaHPO4·2H2O, is a crystalline hydrated acidic form of calcium phosphate that occurs in both physiological and pathological biomineralization processes. Additionally, it is biocompatible in humans. Several groups have investigated the experimental Fourier transform infrared vibrational spectrum of brushite. These investigations have led to a long-standing debate concerning the correct assignment for a few of the observed frequencies, particularly, the water stretching and libration modes. Here, we perform a comprehensive first principles theoretical investigation of the vibrational spectrum of brushite with calculations based on dispersion-corrected density functional theory. We obtain both the vibrational frequencies, using the frozen phonon approach, and their corresponding peak intensities, based on the Born effective charge tensor. This allows for an unambiguous assignment of all vibrations, including water vibration and libration modes.

Heinz A. Lowenstam’s discovery in 1967, together with Ken Towe that the magnetite mineral in mature chiton teeth forms from a disordered transient precursor phase, ferrihydrite, remained an isolated curiosity for 30 years. During the last 15 years, many more examples were found in both invertebrates and vertebrates, where the mature crystalline mineral phase is formed through a transient amorphous precursor phase. Here we review this widespread phenomenon, and also describe the details of the transformation process in the formation of the calcitic spicules of the sea urchin larva. We identify many open questions.

A rapid phytolith extraction procedure is described, that allows phytolith concentrations and morphotype assemblages to be analyzed within hours. This procedure enables the results of these analyses to be used during an archaeological excavation, in order to better understand how plants were used. The new procedure was tested using a standard phytolith extract and two experimental phytolith-sediment blends and found to be both accurate and precise. The reliability of partial slide counting was evaluated and found to be as accurate and precise as existing phytolith quantification methods. The new extraction and counting procedures were applied to an archaeological site, Tell es-Safi/Gath, Israel. The results demonstrate how information on phytolith concentrations in sediments that are available from one day to the next, can be used during an excavation to more effectively document the local features of interest and obtain better information.

A small-angle x-ray scattering study of dispersed crystals from rat bone and mineralized turkey tendon shows that the particles in both preparations have the same scattering behavior. The data are very similar to those reported by Fratzl et al. for intact turkey tendon and are consistent with the crystals being plate shaped. These observations have important implications for understanding both the structure and mineralization processes of these tissues.

Biomineralization is an inherently structural subject; the structure of the mineral phase, the structure of the matrix composed of macromolecules and especially the structure of the interphase zone between them. Studies of the dynamics of mineral formation have revealed that a widespread strategy used by many organisms is to first form a disordered mineral phase. Only when it is in place and has adopted its appropriate shape, is it induced to crystallize. Matrix studies have highlighted the importance of a unique group of proteins that are rich in aspartic acid. These are involved in controlling mineral formation. Relating structure to function in mineralized tissues, often involves an understanding of mechanical properties in terms of not only the hierarchical structure of the tissue, but also the graded structure that varies from one location to another. Structure is thus in many respects the foundation upon which the field of biomineralization rests.

During bone formation in embryos, large amounts of calcium and phosphate are taken up and transported to the site where solid mineral is first deposited. The initial mineral forms in vesicles inside osteoblasts and is deposited as a highly disordered calcium phosphate phase. The mineral is then translocated to the extracellular space where it penetrates the collagen matrix and crystallizes. To date little is known about the transport mechanisms of calcium and phosphate in the vascular system, especially when high transport rates are needed and the concentrations of these ions in the blood serum may exceed the solubility product of the mineral phase. Here we used a rapidly growing biological model, the chick embryo, to study the bone mineralization pathway taking advantage of the fact that large amounts of bone mineral constituents are transported. Cryo scanning electron microscopy together with cryo energy dispersive X-ray spectroscopy and focused-ion beam imaging in the serial surface view mode surprisingly reveal the presence of abundant vesicles containing small mineral particles in the lumen of the blood vessels. Morphologically similar vesicles are also found in the cells associated with bone formation. This observation directly implicates the vascular system in solid mineral distribution, as opposed to the transport of ions in solution. Mineral particle transport inside vesicles implies that far larger amounts of the bone mineral constituents can be transported through the vasculature, without the danger of ectopic precipitation. This introduces a new stage into the bone mineral formation pathway, with the first mineral being formed far from the bone itself.

The Upper Palaeolithic of the Levant (45 000–22 000 BP) represents the full establishment of modern human behavior in this region following the existence of both modern humans and Neanderthals during the Middle Palaeolithic. The Levantine Upper Palaeolithic shares some similarities to its European counterpart but otherwise is quite different.

Bone mineral solubility is an important parameter for understanding the preservation of bones in the archaeological and palaeontological records. In this study we have measured the solubility of the carbonated hydroxyl apatite of sub-recent and fossil bones, as well as synthetic hydroxyl apatite in deionized water and in pH-buffered solutions. The solutions were open to the atmosphere and the pH values were around neutral; measurement conditions that are relevant to bone mineral preservation in nature, but that were absent from most previous studies. We obtained internally consistent results from both the water and the buffered experiments supporting the notion that we are measuring an inherent property of the mineral phase. We found that bone mineral is much more soluble than synthetic hydroxyl apatite. We measured the ionic activity products at “steady state” conditions and we identify a recrystallization window between pH 7.6 and 8.1, which defines the conditions under which bone crystals dissolve and reprecipitate as a more insoluble form of carbonated hydroxyl apatite. As these conditions are common in nature, most fossil bones will not maintain their original crystals with time. We also found that bones that contained small amounts of calcite did not dissolve at all during our experiments. These results provide a basis for better understanding the conditions in sediments under which bones are preserved and the relative states of preservation of bone. They also have important implications for the selection of the most appropriate bone samples for paleoenvironmental and paleodiet analyses and dating.

Amorphous calcium carbonate (ACC) in its pure form is highly unstable, yet some organisms produce stable ACC, and cases are known in which ACC functions as a transient precursor of more stable crystalline aragonite or calcite. Studies of biogenic ACC show that there are significant structural differences, including the observation that the stable forms are hydrated whereas the transient forms are not. The many different ways in which ACC can be formed in vitro shed light on the possible mechanisms involved in stabilization, destabilization, and transformation of ACC into crystalline forms of calcium carbonate. We show here that ACC is a fascinating form of calcium carbonate that may well be of much interest to materials science and biomineralization.

Excerpts from an interview with Stephen Weiner, who recounts his experience in the mental health care system from being told he had an emotional disturbance as a child (1957–1958) to his work with a psychiatrist on strengthening his more rational self. As a child, he was not given a diagnosis, making it difficult to know how “objectively” to evaluate his condition. Probably little was known about the phenomenology of derealization and solipsism then. After college he decided to seek treatment for his growing depression and alcohol abuse under a method known as Rolfing. He describes his skepticism toward psychiatrists and allied professionals unwilling to explain the scientific basis of their treatment. He suggests that the switch to the biological model of mental illness, while mostly good, brought about new difficulties for patients. After seeing three different doctors, Weiner settled with a psychiatrist who offered relief and palliative care.

Understanding the cause of patchy bone distributions in archaeological sites requires that one distinguish bone decomposition in place from “empty” areas where bones were never present. Marked horizontal variations in bone abundance are found in the thick Mousterian layer (E) of Hayonim Cave, a large Paleolithic site in northern Israel. Infra-red analyses of minerals in the sediments identify zones of advanced diagenesis and decomposition alongside zones whose chemistry clearly favoured the preservation of bones and wood ash. These differences adhere closely to the distribution of recognizable bones in the deposits, indicating that spatial variation in bone abundance is essentially a product of differential preservation conditions. However, the few bones present in the bone-poor units are in surprisingly good condition. The higher degree of abrasion damage and more random orientations of these bones indicate that small amounts of recent material were introduced into older layers by small burrowing animals and perhaps localized trampling. The ratio of post-Mousterian to Mousterian artifacts in layer E, and the numeric contrasts in bone abundance among stratigraphic units, indicate that time-averaging from mechanical intrusion was quantitatively unimportant (2–5%) throughout this>2·4 m thick layer. Our findings support Karkanas et al . (2000) suggestion that bone and ash mineral diagenesis in caves follow step-wise rather than gradual transformations in geological time. Good preservation environments can be distinguished from poorer ones on the basis of mineral assemblages in sediments, and deposits that once contained bone and wood ash can be identified long after the visible traces of these materials have disappeared.

Organisms have been producing mineralized skeletons for the past 550 million years. They have evolved many different strategies for improving these materials at almost all hierarchical levels from Angstroms to millimetres. Key components of biological materials are the macromolecules, which are intimately involved in controlling nucleation, growth, shaping and adapting mechanical properties of the mineral phase to function. One interesting tendency that we have noted is that organisms have developed several strategies to produce materials that have more isotropic properties. Much can still be learned from studying the principles of structure–function relations of biological materials. Some of this information may also provide new ideas for improved design of synthetic materials.

Scanning electron micrographs of fractured surfaces of mineralized bone show a lamellar structure with alternating smooth and rough regions. These have been interpreted as corresponding to two distinct collagen fibril and mineral crystal orientations in a rotated plywood structure. However, in various bones, there are clear indications of transition zones between lamellae in which the fibrils, as well as the plate-like crystals, have intermediate orientations. Strong evidence for intermediate collagen fibril orientations comes from vitrified cryo-sections of demineralized bone. These show zones of fibril segments graded in length between more homogenous regions of fibrils roughly parallel to the specimen section. Evidence for intermediate crystal orientations comes from transmission electron micrographs and electron diffraction patterns of crushed bone fragments. A tentative scheme is presented for an interlamellar transition zone, involving rotation about the collagen fibril axis as well as tilting of this axis parallel to the plane of the interlamellar boundary. Although it may be convenient to think of the structure of lamellar bone as being composed of alternating thick and thin lamellae, it is probably more correct and biologically more relevant to consider one pair of lamellae as the product of a single depositional cycle of varyingly oriented collagen fibrils that subsequently mineralize. © 1996 Wiley-Liss, Inc.

Organisms can exert a remark- able degree of control over crystal growth. One way of achieving this is by the ad- sorption of specialized macromolecules on specific planes of the growing crystals. With continued growth of the crystal, the macromolecules are incorporated inside the crystal bulk. Their presence does not change the crystal structure, but creates discontinuities in the perfect lattice. Here we study in detail three unusual cases of reduction in symmetry at the level of crys- tal domain shapes, induced by this con- trolled intercalation. We examined sponge spicules, which are single crystals of Mg- bearing calcite. They were specifically chosen for this study, because their mor- phologies do not reflect the hexagonal symmetry of calcite. Their crystal textures (coherence lengths and angular spreads) were characterized by high-resolution X- ray diffraction with well-collimated syn- chrotron radiation. The results are com- pared to analogous studies of synthetic calcite and Mg-bearing calcite. In all the selected spicules reduction in symmetry is observed in the coherence lengths among symmetry-related crystallographic direc- tions. The reconstructed shapes of the do- mains of perfect structure closely match the specific spicule morphologies. The synthetic crystals show no such reduction in symmetry. Although the manner by which such exquisite control is achieved is not known, we envisage it involving a combination of oriented nucleation with either physical or stereochemically driven adsorption.

This paper presents research on the conditions under which progressive levels of burning may occur to archaeological bone, and how burning damage changes bones' crystal structure and susceptibility to fragmentation (a.k.a. friability). Experiments were conducted to simulate common patterns of high-temperature bone diagenesis and fragmentation previously documented in Paleolithic shelter sites. Bones buried up to 6 cm below the coal beds of the experimental fires were carbonized, but calcination occurred only with direct exposure to live coals. Analysis by infra-red spectroscopy reveals that marked changes in crystallinity accompany the macroscopic transformations in colour and friability of modern, fire-altered bone; specifically, a monotonic, non-linear decrease in mean fragment length across six colour categories was observed when samples were agitated or trampled, and a concordant decline in bone identifiability, first with respect to skeletal element and ultimately the recognizability of bone tissue itself. These findings help qualify the behavioural and taphonomic implications of fragmented, burned bones in archaeological sites, especially with regard to potential stratigraphic associations between artefacts and hearth features in sites and the intensity of space use by human occupants. The identification of burning damage on archaeological bone is a separate issue, however. It was found that the molecular signatures of recrystallization in modern burned bones partly overlap with recrystallization caused by weathering after only 1 to 2 years of exposure in an arid setting and by partial fossilization of archaeological bones over the long term. While infra-red and X-ray diffraction techniques effectively describe heat-induced changes in modern bone mineral and are an important aid for modelling diagenetic processes, these techniques did not reliably identify burning damage to archaeological bones. Cross-referencing readily visible colour phases with HCl-insoluble fraction data proves much more effective and economically feasible for the latter purpose.

The mineral assemblages in prehistoric sites can provide essential information on several important topics in archaeology. One of the key analytical tools used is Fourier-transform infrared spectrometry, which is operated both on-site during the excavation and in the laboratory. Three topics are reviewed here based on studies of Hayonim and Kebara caves in Israel. (1) Reaction rims form on calcitic and dolomitic rocks buried in the sediments. They are normally the result of interaction of the rock minerals with phosphate-rich groundwater. The mineralogical nature of these reaction rims can be indicative of prevailing chemical conditions in the sediments, which in turn provide information on whether or not bones are preserved at the site, or are preserved at specific locales within the site. Thus, a survey of reaction rims can be helpful in determining the potential of a future excavation site, or areas within a site, and for optimizing excavation strategies during an ongoing project. (2) The preservational states of the bones themselves, together with information on the mineralogical nature of some of the more labile sediment components, can be used for ascertaining whether or not the bone distribution patterns as excavated represent the original burial locations, or have been affected by secondary dissolution of bones in some areas and not others. (3) The ashes from wood fires are a major component of the sediments in both caves studied. Understanding and monitoring the complex series of diagenetic changes that ashes undergo in these environments can provide invaluable information, not only on the manner in which fire was used by the cave occupants, but also on a series of important processes that affect the depositional history of the site itself. The study of mineral assemblages in prehistoric cave sites, as illustrated here with 3 examples, and possibly in open-air sites as well, has the potential for contributing significantly to a better understanding of many archaeological problems.

Bone and tooth mineral generally undergo diagenetic changes. These changes in the carbonate hydroxyapatite structure and composition can affect the signals embedded in the mineral phase, such as migration behavior, age of the specimen and the reconstruction of past environments. Mineral preservation state can be assessed using infrared spectroscopy which provides information on crystal disorder at the atomic level and mineral composition. Here we present a new approach to evaluate carbonate hydroxyapatite atomic disorder using infrared spectroscopy and the standard KBr sample mounting method. We show that by repeated grinding of the sample and then plotting the infrared splitting factor against the width of the major phosphate absorption peak after each grinding, grinding curves with well defined trend lines can be obtained. The offsets between curves reflect differences in atomic disorder. We show that grinding curve offsets can be used to evaluate the state of preservation of bone, dentine and enamel mineral. Les os et les dents subissent généralement des changements diagénétiques. Ces changements de la structure et de la composition de l’hydroxyapatite carbonatée peuvent affecter les signaux inclus dans la phase minérale, tels que les comportements de migration, l’âge des spécimens ou la reconstitution des environnements passés. L’état de préservation de la phase minérale peut être déterminé par la spectrométrie infrarouge qui fournit des informations sur le désordre structural et sur la composition du minéral. Dans cette étude, nous présentons une nouvelle approche permettant d’évaluer le désordre cristallin en utilisant la spectrométrie infrarouge. Nous montrons ici qu’un broyage répété de l’échantillon et la représentation graphique des valeurs de splitting factor et de la largeur à mi-hauteur de la principale bande d’absorption des phosphates après chaque broyage, peut permettre de définir des courbes de broyage avec des tendances bien définies. Un décalage entre ces courbes reflète des différences de désorganisation à l’échelle atomique.

Bone samples from patients suffering from osteogenesis imperfecta (OI) types I, II, III and IV, as well as normal controls, were studied by scanning (SEM) and transmission electron microscopy (TEM). SEM views of normal bone at low magnification show coherent structure, with regular striations due to a lamellar plywood like arrangement of the mineralized collagen fibrils. Compact lamellar bone was also found in various OI specimens, but in limited disconnected regions separated by open spaces. Furthermore, some OI, but not normal, bones have regions of loose unconnected fibers and others of apparently abnormally dense mineral deposition. High resolution TEM studies of OI bone fragments have served to elucidate the structures of these different textures. There appears to be a substantial, though reduced, proportion of normal lamellar bone even in quite severe OI. However, the regions of loose fibers are largely unmineralized and probably contain abnormal collagen. Other regions are overmineralized, with generally small unorganized apatite crystals deposited onto fibril surfaces or in separate clusters. These structural abnormalities, together with the paucity of normal bone, may explain the fragility of OI bones.

A vital factor in the rise of the first state societies is the development of complex farming systems employing labour-intensive irrigation. Ancient irrigation is, however, difficult to recognize archaeologically. Here we report a new method for identifying ancient irrigation based on recognizing the increased deposition of silica in irrigated cereals. Our experiments showed that emmer wheat grown with irrigation in semi-arid plots produced phytoliths with greater numbers of silicified cells per phytolith than wheat that was dry-farmed. The presence of such large multi-celled phytoliths in semi-arid archaeological sites can be used as evidence for prehistoric irrigation.

The distribution of bones in Kebara Cave, Israel, is very heterogeneous. In order to address the question of whether the bone concentrations were created secondarily by differential dissolution, or represent the original burial distributions, a portable Fourier-transform infrared spectrometer (FTIR) was operated on-site. It was used to map the distribution of the minerals in the sediments, in order to delineate the zone in which original ash-derived calcite was preserved, as well as the zone in which carbonate apatite (dahllite) was still preserved. The bone distribution in the former zone must be primary, as calcite is less stable than dahllite, the mineral phase of bone. The boundary between the zone containing dahllite in the sediments and the zone in which it was absent, also essentially mapped the southernmost distribution of bones in the cave. The distribution of bones in the dahllite zone is thus also likely to be original. Supporting this notion was the observation that the bones at the periphery of the concentrations were not less well-preserved than those in the centre, except at one location which coincided with the boundary of the dahllite zone. In the third zone, the bones appear to have been lost by dissolution. The operation of an FTIR on-site proved to be an efficient and useful method for resolving this important archaeological problem.

A unique set of proteins extracted from a variety of invertebrate calcitic mineralized tissues is able to selectively interact in vitro with certain crystal faces and not others. This was previously demonstrated by observing changes in morphology of crystals grown in the presence of proteins as compared to those grown in the absence of proteins. Following interaction, the proteins are overgrown by the crystal and are subsequently occluded within the crystal itself. Here we address the fundamental question of whether or not the proteins also alter the crystal texture in an anisotropic manner. For this purpose we used high-resolution synchrotron X-ray diffraction to monitor changes in coherence length and angular spread

The archaeological record is mainly composed of materials related to past human behavior. Some of these are visible to the naked eye – the so-called macroscopic record – and some require instruments, such as microscopes or spectrometers, to be seen and characterized. This is the so-called microscopic record, and the study of this record is referred to here as microarchaeology . The macroscopic record is composed of strata, buildings, graves, floors, and so on, as well as artifacts such as pottery, bones, stone, and metal tools. The microscopic record is composed of the materials of which the macroscopic artifacts are made, as well as the sedimentary matrix in which the artifacts are buried. Thus the investigation of the archaeological record as a whole involves the integration of both the macroscopic and microscopic records. It incorporates activities that span the humanities, social sciences, and natural sciences, with the former two disciplines being focused mainly on the macroscopic record and the latter discipline being focused mainly on the microscopic record. Herein lies a problem: the different parts of the archaeological record are studied by investigators with diverse backgrounds and approaches. Often lacking is an integration of these different worlds. In this book, the focus is on the archaeological information that can be extracted from the microscopic record and, in particular, from the materials commonly found in most archaeological sites such as ceramics, bones, rocks, ash, and sediments.

The macroscopic record (what you see with the naked eye) and the microscopic record (what you “see” with the aid of technology) together constitute the archaeological record. All the information that we can learn about past human behavior is embedded in this combined record. The first requirement for exploiting the microscopic record is to have an overview of the types of information that can be obtained from the record, and to understand the basic principles on which this information is based; the subject of this chapter. This chapter provides brief overviews of many, but not all, of the different categories of information that are embedded in the microscopic record. The chapters following this chapter provide information on various common materials that are present in archaeological sites, underlying mechanistic processes that influence the preservation of these materials, and at the end of each chapter or subsection, more information is given on the embedded information that can be extracted from these materials. Emphasis is placed on the concepts rather than the methods. For a review of the most common methods used to extract information from the microscopic record and the principles on which these methods are based, see chapter 2 of the work by Pollard and Heron (2008). It is noteworthy that many of the methods used to extract information from the microscopic record were not developed by archaeologists. They were developed mainly by chemists, geochemists, botanists, and others for their own purposes and were later adapted and applied to archaeological problems.

Humans have used fire for at least half a million years, and possibly a million or more years (Brain and Sillen, 1988; James, 1989; Weiner et al., 1998; Goren-Inbar et al., 2004). During this entire period, the most common use of fire was presumably for cooking food, for producing light and warmth, and for protection. It was only about 15,000 to possibly 18,000 years ago that fire was used for the first time to produce synthetic materials: plaster in the southern Levant (Kingery et al., 1988; Valla et al., 2007) and ceramics in south China and Japan (Yasuda, 2002; Boaretto et al., 2009c). All deliberate uses of fire by humans are referred to here as pyrotechnology . This behavior is one of the unique attributes of our species. Pyrotechnological practices are therefore of much interest when reconstructing human behavior. Pyrotechnology is based on the fact that heat causes a usually atomically ordered natural material to lose its order, change its form, and then, on cooling, adopt another arrangement of atoms that results in the new material having different properties. Cooking is perhaps the most widespread and ancient form of pyrotechnology. In the case of plaster, ceramics, metals, and glasses, the new material can also be conveniently shaped. The shaping capability, together with the advantageous material properties, are the main functional and/or aesthetic benefits of producing traditional synthetic materials.

Biologically produced mineralized materials are an important component of the archaeological record. The most common biogenic materials found in archaeological sites are bones, teeth, mollusk shells, eggshells, otoliths, and plant phytoliths. The fact that they are mineralized greatly increases their chances of being preserved, and as they are biologically produced, they contain much embedded information of interest to archaeology. BIOMINERALIZATION: ARCHAEOLOGICAL PERSPECTIVE The biogenic mineralized materials common in archaeological sites are part of a much larger group of mineralized materials produced by a wide variety of organisms, ranging from bacteria to man (for overviews, see Lowenstam and Weiner, 1989; Simkiss and Wilbur, 1989; Dove et al., 2003). More than 65 different minerals are known to be produced biologically. These include minerals that, at the atomic level, are highly disordered such as amorphous silica (opal), amorphous calcium carbonate, and amorphous calcium phosphate. Most biogenic minerals are relatively ordered at the atomic level and are thus crystalline. Common crystalline biogenic minerals include the carbonate minerals (such as calcite, aragonite, vaterite, and monohydrocalcite), the calcium phosphate mineral carbonated apatite, oxides (such as the magnetic mineral magnetite), calcium oxalates, and more. For a partial list, see Appendix B. Biogenic minerals usually have shapes that are quite distinct from their inorganic counterparts and are often aligned into arrays. Biogenic mineral assemblies almost always have intimately associated organic components, some of which are responsible for controlling mineral formation. The mineralization process, like all biological processes, is orchestrated by cells.

The identification of materials and their characterization is, in many respects, the key to elucidating the microscopic archaeological record. Among all the methods used for this purpose in archaeology, infrared spectroscopy is one of the most useful. Infrared spectra are easy to obtain but can be difficult to interpret. The purpose of this chapter is to provide information on interpreting infrared spectra of archaeological materials as well as to review some of the more common applications. The latter are referred to as overviews in this chapter and throughout the book. Infrared spectroscopy is a sensitive method for obtaining information on the molecular structures of crystalline and amorphous/ disordered materials as well as organic materials. Infrared spectroscopy can thus be used both to identify materials and to characterize their states of atomic order and disorder. In these respects, infrared spectroscopy is similar to powder X-ray diffraction, although the latter cannot be used to identify and characterize amorphous and highly disordered materials. Amorphous and highly disordered materials are common in archaeology. Infrared spectroscopy is based on the manner in which radiation interacts with material in the infrared range (4,000 to 250 centimeter −1 [cm –1 ; wavenumbers, or the inverse of wavelength]). Some of this radiation is absorbed by the sample because it causes the chemical bonds of the sample to vibrate. The result is that less radiation reaches the detector at specific wavenumbers, and this is recorded as a series of peaks in the infrared absorbance spectrum.

The archaeological record is a combination of what is seen by eye, as well as the microscopic record revealed with the help of instrumentation. The information embedded in the microscopic record can significantly add to our understanding of past human behaviour, provided this information has not been altered by the passage of time. Microarchaeology seeks to understand the microscopic record in terms of the type of information embedded in this record, the materials in which this information resides, and the conditions under which a reliable signal can be extracted. This book highlights the concepts needed to extract information from the microscopic record. Intended for all archaeologists and archaeological scientists, it will be of particular interest to students who have some background in the natural sciences as well as archaeology.