ABSTRACT Travertine deposits preserved within ancient aqueduct channels record information about the hydrology, temperature, and chemistry of the flowing water from which they precipitated. However, travertine is also chemically reactive and susceptible to freshwater diagenesis, which can alter its original composition and impact reconstructions of aqueduct operation, maintenance, and climate. Hydraulic reconstructions, in combination with a suite of high-resolution optical, laser, electron, and X-ray microscopy analyses, have been used to determine the original crystalline structure and diagenetic alteration of travertine deposited in the Anio Novus aqueduct built in A.D. 38–52 at Roma Vecchia. Age-equivalent travertine deposits, precipitated directly on the mortar-covered floor at upstream and downstream sites along a 140-m-long continuous section of the Anio Novus channel, exhibit consistent crystalline textures and stratigraphic layering. This includes aggrading, prograding, and retrograding sets of travertine linguoid, sinuous, and hummocky crystal growth ripples, as well as sand lags with coated siliciclastic grains deposited on the lee slope of ripple crests. The original aqueduct travertine, which is similar to travertine formed in analogous natural environments, is composed of shrub-like, dendritically branching aggregates of 1–3-μm-diameter euhedral calcite crystals. Dark brown organic matter-rich laminae, formed by microbial biofilms and plant debris, create stratigraphic sequences of high-frequency, dark–light layering. This hydraulic and petrographic evidence suggests that large, radiaxial calcites diagenetically replaced the original aqueduct travertine shrubs, forming upward-branching replacement crystals that crosscut the biofilm laminae. While this diagenetic process destroyed the original crystalline fabric of the calcite shrubs, the entombed biofilm laminae were mimetically preserved. These integrated approaches create the type of depositional and diagenetic framework required for future chemostratigraphic analyses of travertine deposited in the Anio Novus and other ancient water conveyance and storage systems around the world, from which ancient human activity and climatic change can be more accurately reconstructed.

Abstract Échaillon stone, a Mesozoic platform limestone from SE France, is proposed as a Global Heritage Stone Resource. The Échaillon stone quarries are located at the western termination of the Alps, near the city of Grenoble. Stone from the main Échaillon quarries is an Upper Jurassic to Berriasian bioclastic near-reef limestone, renowned for its two characteristic white and pink colours. Two ancillary quarries nearby, the Lignet and Rovon quarries, provided the Lower Cretaceous (Barremian to Aptian) Yellow Échaillon stone, of lagoonal origin. Échaillon stone's unique characteristics, resistance to weathering and high aesthetic values made it a prized building and ornamental material used in many significant historical buildings in Europe, North Africa and the USA. Although the first use of Échaillon stone in buildings dates from the Gallo-Roman period, the industrial use ranges from the mid-nineteenth century, during the heyday of the Beaux-Arts architecture period in France, to the mid-twentieth century. The reputation of Échaillon stone was bolstered by world-renowned architects, sculptors and artists who used it for historical building ornament and sculptures. By the turn of the twentieth century, production started to decline and it ceased by the middle of that century.

Abstract Old chalk and flint mine workings occur widely across southern and eastern England. Over 3500 mines are recorded in the national Stantec Mining Cavities Database and more are being discovered each year. The oldest flint mines date from the Neolithic period and oldest chalk mines from at least medieval times, possibly Roman times. The most intensive period for mining was during the 1800s, although some mining activities continued into the 1900s. The size, shape and extent of the mines vary considerably with some types only being found in particular areas. They range from crudely excavated bellpits to more extensive pillar-and-stall styles of mining. The mines were created for a series of industrial, building and agricultural purposes. Mining locations were not formally recorded so most are discovered following the collapse of the ground over poorly backfilled shafts and adits. The subsidence activity, often triggered by heavy rainfall or leaking water services, poses a hazard to the built environment and people. Purpose-designed ground investigations are needed to map out the mine workings and carry out follow-on ground stabilization after subsidence events. Where mine workings can be safely entered they can sometimes be stabilized by reinforcement rather than infilling.

Over recent decades, numerous studies have highlighted the importance of opal, chalcedony and quartz varieties, chiefly in volcanic, but also in metamorphic and sedimentary environments. The focus is to define accurately their structures, composition and properties, as well as to identify the factors controlling the formation and the ageing of different forms of silica. In the field of archaeological sciences efficient discriminants are the bases from which the origin and provenance of materials may be traced. Substantial efforts were made in the attempt to combine geochemical, mineralogical, petrographic and geological features with archaeological and archaeometric information. However the results show that data integration is complicated, and several unanswered questions remain. On the one hand, archaeological research has focused on technological and ethnographic aspects, mainly concerning use-wear and heat-treatment studies. Mineralogical characterization has often been limited to the identification of the material, frequently by Raman microspectroscopy alone. On the other hand, the Earth sciences have provided basic mineralogical, crystal-chemical and geological knowledge, but failed to provide a systematic data collection of sources and their geochemistry. As a consequence, large gaps persist in the identification of archaeological opals, chalcedonies and quartz varieties, and in the geographic mapping of possible sources. In this context, the present review aims to summarize the current academic debate on such issues, possibly to encourage further work in the field. After a brief introduction to terminology, the structure of opals, their colours and properties are discussed, followed by an introduction to silica dissolution/precipitation and opal-formation processes. The next section reviews the information available on use of opals and provenance from historical sources, mainly Pliny the Elder, followed by a short list of ancient and modern opal supply areas, together with a (necessarily incomplete) summary of the geological and geochemical information. The discussion then encompasses chalcedony, agate and chalcedony varieties (carnelian, sard, onyx, sardonyx, chrysoprase, Cr-chalcedony, ‘gem silica’ or ‘chrysocolla chalcedony’ and heliotrope), following the same scheme as was adopted for opals. Terminology, distinguishing features, formation conditions, information derived from Pliny’s books, past and current supply areas and, finally, archaeometric provenance issues are addressed for each type of material. As for chalcedony, a comprehensive note on moganite has been included. The next section focuses on chert, flint and jasper. Given the large amount of materials available on this topic, the present review must necessarily be considered introductory and partial. The discussion aims to provide useful indications on how to distinguish chert from flint and chert from jasper; secondly, the information provided by Pliny and the archaeometric state of the art on these materials is reviewed. The last section examines quartz varieties: hyaline quartz (rock crystal), milky quartz, smoky quartz, rose and pink quartz, amethyst, citrine, prasiolite and blue quartz. An exhaustive mineralogical discussion on quartz is beyond the scope of this review; conversely a review of the historical information is provided, together with a brief list of major supply areas, a summary of the archaeometric studies performed on these materials, as well as an indication of the geological literature which can be used proficiently for provenance studies.

Early vitreous materials include homogeneous glass, glassy faience, faience and glazed stones. These materials evolved slowly into more specialized substances such as enamels, engobes, lustres, or even modern metallic glass. The nature and properties of vitreous materials are summarized briefly, with an eye to the historical evolution of glass production in the Mediterranean world. Focus is on the evolution of European, Egyptian, and Near East materials. Notes on Chinese and Indian glass are reported for comparison. The most common techniques of mineralogical and chemical characterization of vitreous materials are described, highlighting the information derived for the purposes of archaeometric analysis and conservation.

Copper was the first metal to have been smelted (extracted from its ore) some seven thousands year ago in the ancient Near East. For most pre-industrial periods, the documentation of copper smelting chaine operatoire relies mainly on investigations by archaeometallurgists of the metallurgical waste recovered during archaeological excavations, namely the copper slags. Copper slags are mostly an assemblage of crystals of oxides (iron, manganese, etc. ), olivine (fayalite, etc. ) and/or pyroxenes embedded in a polymetallic more-or-less glassy matrix. The mineralogy of the slags is directly related to the initial charge and the working conditions prevailing in the pyrometallurgical reactor. This chapter aims to give an overview of how copper slag mineralogy is investigated and the type of information it yields in order to help our understanding of past metallurgies and societies.

This contribution is dedicated to the memory of Professor Ursula Martius Franklin, a true pioneer of archaeometric research, who passed away at her home in Toronto on July 22, 2016, at the age of 94. Making ceramics by firing of clay is essentially a reversal of the natural weathering process of rocks. Millennia ago, potters invented simple pyrotechnologies to recombine the chemical compounds once separated by weathering in order to obtain what is more or less a rock-like product shaped and decorated according to need and preference. Whereas Nature reconsolidates clays by long-term diagenetic or metamorphic transformation processes, potters exploit a ‘short-cut’ of these processes that affects the state of equilibrium of the system being transformed thermally. This ‘short-cut’ is thought to be akin to the development of mineral-reaction textures resulting from disequilibria established during rapidly heated pyrometamorphic events (Grapes, 2006) involving contact aureoles or reactions with xenoliths. In contrast to most naturally consolidated clays, the solidified rock-like ceramic material inherits non-equilibrium and statistical states best described as ‘frozen-in’. The more or less high temperatures applied to clays during ceramic firing result in a distinct state of sintering that is dependent on the firing temperature, the duration of firing, the firing atmosphere, and the composition and grain-size distribution of the clay. Hence, the salient properties of the ceramics have to be assessed in a temperature-time-composition space. Owing to the variability of clay composition, the mineralogical processes during thermal transformation of clay minerals can be very complex, not least because most reactions occur far removed from thermodynamic equilibrium and hence are kinetically controlled; that is, they are time- and temperature-dependent. Indeed, kinetics imposes constraints on thermodynamics by retarding reaction rates because of low temperatures, large temperature gradients present in primitive pottery kilns, short reaction times, inhomogeneously distributed reaction partners, and varying redox conditions triggered, for example, by ingress of air during reducing firing cycles. In the context of ceramic technological development over time, the role and development of pottery technology within complex societies is discussed. The close relationship between pottery development and changes in life/societal organization appears to be a major driver in this endeavour. In this chapter, the phase evolution of some typical ancient and historical ceramics will be traced using ceramic phase diagrams, i.e . chemographical expressions of Goldschmidt’s mineralogical phase rule. In particular, the systems CaO–Al 2 O 3 –SiO 2 (in which most ancient low- to medium-fired ceramics can be accommodated), K 2 O–Al 2 O 3 –SiO 2 (applicable to high-fired Chinese stoneware and European hard-paste porcelain) and Na 2 O–CaO–(Al 2 O 3 )–SiO 2 (typical of some ancient Egyptian and Mesopotamian alkaline glazes and French soft-paste porcelain) are discussed.

From shell beads in the Palaeolithic and stone beads in the Neolithic to beautiful artificial gems in modern times, the history of gems has roughly paralleled that of humans. In the beginning, myths and folklore about the healing properties of gemstones dominated the story. Today, the story is about scientific techniques making larger or more colourful gems and newly discovered mineral deposits revealing gemstone treasures. In the western world the written history of precious and semiprecious stones begins with the On Stones of the Greek philosopher and naturalist Theophrastus ( ca . 315 BC) followed by the Natural History of the Roman historian Pliny (77 AD), which was the standard work on gems and minerals for more than a thousand years. The gemstones of the Old Testament and those of ancient East Asia tell their separate stories. Following a brief summary of these early works, this paper continues with individual descriptions of the major gems and semiprecious stones, focusing on their two most important attributes – colour and hardness – as well as where they are found. This is followed by a brief discussion of altered gems and a summary of modern interactions of gems and man. This paper concludes with some personal experiences of the author and a brief introduction to the geology of gem deposits.

The Romans, like the Egyptians and much more than the Greeks, used polychrome stones for decorative purposes in architectural elements, floor and wall facings and statuary. Throughout their Mediterranean provinces they systematically searched for and exploited a very large number of beautiful lithotypes, many of which they distributed to all corners of their empire. The most important of these stones were often re-used later in medieval-to-modern times; some of them are still offered on the market. They include granitoid rocks (granites, granodiorites/tonalities, gabbros, quartz-monzonites), a few lavas, many metamorphites (impure marbles, metabreccias and metandesites) and several sedimentary rocks (limestones, lumachellas, conglomerates, calcareous alabasters/travertines). The 40 most important and widespread of these lithotypes are considered here as regards their origin, the history of their use and their minero-petrographic characteristics, which can contribute to better knowledge of single species, to determination of the original quarries and to archaeometric solutions of several provenance problems.