gems, ancient reference, archaeology, ancient trade, commerce, archaeogemology, Mesopotamia, cosmic geography

Mesopotamian Cosmic Geography represents the main part of my first decade of study as an Assyriologist. The book began its life as a Ph.D. thesis of the same name under the supervision of Professor W. G. Lambert of the University of Birmingham. After completion of the Ph.D. thesis in 1986, I continued to collect materials relevant to the study of Mesopotamian views of cosmography with the intention of revising the thesis as a book in the early 1990s. The book Mesopotamian Cosmic Geography presents this revised, more mature examination of the topic.

gems, obsidian, natural glass, archaeology, archaeogemology, Sardinia

This volume is the third in the Advances in Archaeological and Museum Science series sponsored by the Society for Archaeological Sciences (SAS). The purpose of this series is to provide summaries of advances in various topics in ar­ chaeometry, archaeological science, environmental archaeology, preservation technology, and museum conservation. The SAS exists to encourage interdisciplinary collaboration between archaeologists and colleagues in the natural and physical sciences. SAS mem­ bers are drawn from many disciplinary fields. However, they all share a common belief that physical science techniques and methods constitute an essential component of contemporary archaeological field and laboratory studies. The series editors wish to thank the reviewers of each of the chapters in this volume for their excellent comments and suggestions. We also wish to thank Chriss jones for her invaluable assistance in the preparation of the texts for submission to the publisher. xi Preface As noted in the introductory chapter, this volume is the second major review of research progress in the study of archaeological obsidian. An earlier book, Advances in Obsidian Glass Studies: Archaeological and Geochemical Perspectives, appeared in 1976. A comparison of the treatment of topics reflected in this earlier work and that contained in this volume not only highlights important advances in the quality and depth of research on archaeological obsidian over more than a quarter of a century but also illustrates more generally some characteristics of developments in the archaeological science field in general.

gems, archaeology, archaeogemology, Africa, East Africa, Tanzania, Kenya

This is a preliminary report of an archaeological reconnaissance conducted in the Rufiji District, Coast region in July and August 1996. The district of Rufiji comprises the whole of the Rufiji delta, some few off-islands near the delta, and the immediate hinterland of the delta extending to about 100 km into the interior. The district is on the central coast of East Africa, about 100 km south of Dar-es-Salaam, Tanzania from latitude 7°35’ to 8°00’ S and longitude 38°30’ to 39°20’ E (Map 1). The archaeological research was organized by the Archaeology Unit of the University of Dar es Salaam as field training for archaeology students. The Archaeology Unit has annual field school sessions, which involve, apart from training, archaeological survey and excavations.

gems, Russia, Ural Mountains, Saranovskoye, uvarovite garnet, Cr-grossular- Cr-sphene

Gem-quality minerals, including uvarovite, Cr-grossular and Cr-titanite, associated with the Saranovskoye chromite deposit, northern Urals, are described. The geology and mineralogy of the deposit indicates its formation following a well-known cycle of low-grade metamorphic processes and hydrothermal activity.

gems, jade, Russia, China, Mongolia, Japan, Eurasia, archaeology, archaeogemology

This major work, the result of collaboration among scholars who worked at dozens of sites from the Ural Mountains to the Pacific Ocean, is the first volume in English to summarize the massive quantity of archaeological data on the Paleolithic occupation of Siberia. Written by leading Russian experts and edited by scholars including the late Demitri Shimkin, the book presents the results of field studies conducted over some twenty-five years. It traces the routes of human migration throughout Eurasia, shows Siberian lithic industries as they evolved from the Early through the Middle and Late Paleolithic, and correlates them with reports from Mongolia, China, Japan, and America.

gems, beryl, emerald, Brazil, inclusions

Emerald crystals from the Campos Verdes mining district have been analysed by inductively coupled plasma mass spectrometry (ICP-MS), Fourier transform infrared spectroscopy and Mössbauer 2+ 3+ spectroscopy. These gems contain measurable amounts of Fe , Fe , Cr, V, Sc, Ni and Zn; large-ion lithophile element (LILE, Ba, Sr, Rb, Pb) and high field strength element (HFSE, Zr, Y, Ti) contents are near or below the limit of detection. This chemical signature reflects the metasomatic reactions between the mineralizing fluids and the ultrabasic host-rocks of this gem deposit.

corundum, inclusions.5, Sri Lanka.12, gems

Carbonin, Sbrignadello, and Ajò demonstrate the value of combining independent analytical techniques to identify solid inclusions in corundum through a study of a commercially obtained blue sapphire containing thorite. The stone was provisionally assigned to a Sri Lanka type on the basis of an experienced supplier’s assessment, but reliable information establishing its geographical provenance was unavailable. Transmitted-light microscopy revealed at least two visually distinct inclusion types. A red, well-formed octahedral crystal associated with fingerprint inclusions was considered to be chromium-bearing spinel, a feature previously described in Sri Lankan sapphire. Photoluminescence measurements were undertaken with helium–neon laser excitation and subsequently with a more intense argon laser because the initial chromium-related emission from the host sapphire was weak and noisy. The principal identification problem concerned a second inclusion, approximately 45 µm long, whose habit, surrounding tension haloes, and fissures initially suggested metamict zircon. Because this grain lay close to the sapphire’s surface, the host was polished until the inclusion was exposed for electron microprobe examination. Energy-dispersive analysis unexpectedly detected no characteristic zirconium radiation. Instead, silicon and several diagnostic thorium emissions dominated the spectrum, supporting identification as thorite, ThSiO₄, whose crystal habit closely resembles that of zircon. The grain’s extremely small size prompted confirmation by an independent method. Low-background gamma spectrometry using an intrinsic germanium detector established the presence of natural thorium-232 through characteristic emissions from its radioactive daughter products, lead-212 and thallium-208, at 238.6 and 583.1 keV, respectively. The agreement between elemental microanalysis and nuclear spectrometry strengthened the thorite identification beyond what could be inferred from optical appearance alone. The authors emphasize that their complementary methods probe different physical processes, involving electronic and nuclear energy levels, and therefore provide independent support when a microscopic identification is uncertain. The study cautions against assigning zircon solely from crystal morphology and associated stress features, since another radioactive silicate can present a similar appearance. It also suggests that thorite should be considered among the inclusion species potentially relevant to sapphire provenance investigations, while the uncertain source of the specimen prevents its use as firm evidence of a Sri Lankan occurrence.

corundum, Tajikistan.12, ruby, gems

Smith characterizes rubies and pink sapphires from marble-type deposits in the Turakuloma region of Tajikistan’s Pamir Mountains through examination of eight gemstones weighing 0.30–1.48 ct. Discovered in the early 1980s, these deposits had supplied only limited quantities to the international market. The best-known mine, Snejnaya, lies at approximately 3500 m, where severe weather restricts mining largely to June–August. The investigation combines standard gemological testing, immersion microscopy, identification of mineral inclusions by scanning electron microscopy with energy-dispersive analysis, optical and infrared spectroscopy, and semiquantitative X-ray fluorescence analysis. Samples are transparent, with saturated purplish-pink to purplish-red colours. Refractive indices of 1.761–1.762 and 1.770, birefringence of 0.008–0.009, specific gravity of 3.99–4.02 and uniaxial negative optic character are consistent with ruby and pink sapphire generally. Long-wave ultraviolet fluorescence is strong to very strong orange-red to red, while short-wave reactions are weaker. Internal growth structures indicate predominantly dipyramidal habits, with subordinate basal and rhombohedral faces; occasional colour zoning and rhombohedral twin lamellae are also recorded. Particularly useful microscopic features include columnar concentrations of short rutile needles and particles, highly resorbed calcite crystals arranged in roughly parallel rows, and small mineral or negative crystals accompanied by oriented equatorial thin films. Additional inclusions comprise titanite, zircon, rutile and plagioclase feldspar, together with healed fractures and negative crystals containing multiple fluid phases. Visible absorption is dominated by chromium, with broad bands near 405 and 550 nm and characteristic sharp lines. Infrared spectra show the expected corundum lattice absorptions but no detected mid-infrared features attributable to foreign minerals or structural hydroxyl groups. Analyses of five specimens identify chromium as the principal minor element responsible for colour, accompanied by titanium, vanadium, iron and gallium. Although the stones most closely resemble material from Quy Chau, Vietnam, their combined inclusion patterns appear distinctive and differ from features commonly encountered in several other ruby sources. Smith emphasizes the small sample population and the limited information available on production and reserves. At the time of writing, civil conflict, financial constraints and difficult access restricted exploitation, while fine faceted stones were generally 1.5 ct or smaller.

gems, jade, pyroxene jade, fei cui, Guatemala, Mesoamerica, Nicaragua, Mexico, Honduras, Costa Rica, archaeogemology, Cuba, Dominican Republic, geology

Jadeitite occurs along with albitite (ex-jadeitite) in blocks in tectonised serpentinite, or more often in river pebbles, along the Motagua River Valley and its tributaries (MRV) in Guatemala (e.g. McBirney et al., 1967; Harlow, 1994). The MRV is generally considered to be the source area for most, if not all, of the jade used widely in the prehispanic civilisations ranging from the Olmecs through the Mayas to the Aztecs (e.g. Hargett, 1990; Harlow, 1991). Harlow (1994) mentioned the evident spatial relationships of known jadeitite or eclogite occurrences with the major suture contact of the North American and Caribbean Plates (which runs W.S.W.-E.N.E. precisely along the MRV), and he emphasised that jadeitite and eclogite are respectively restricted to the North and South sides of the MRV. Raman Microprobe (RMP) analysis on the unprepared small (~4×2×2 cm) green river pebble n° FG96/27, collected from the South side of the MRV, showed it to be a near monomineralic jadeitite with a composition of 90 ± 10 mol% Jd, with a characteristic T-O-T vibration at 697–701 cm⁻¹ (cf. Smith & Boyer, 1985; Smith & Gendron, 1997). Both macro- and micro-mode RMP also revealed local enrichments of rutile, a mineral not listed in the comprehensive study of MRV jadeitites by Harlow (1994). A subsequently manufactured thin section revealed: an irregular granular microcrystalline texture with the pyroxene (~97 vol%, i.e. true jadeite jade) sometimes showing optically-zoned grain boundaries; abundant rutile (~2 vol%); rare titanite and zircon; and more importantly numerous micron-sized inclusions in the cores of a few of the larger equant to elongate jadeite grains. EMP analysis then proved 77 to 97 mol% Jd. All analysed microinclusions are quartz (also not listed by Harlow, 1994), thus indicating a trapped core assemblage on the higher P side of the Ab = Jd + Qz reaction for the given compositions. No other mineral species have been found, in particular no albite, nepheline nor analcime, and hence no retrogression at all. Jadeitite n° FG96/27 is thus very different from all the varieties of jadeitite from the North side of the MRV described by Harlow (1994). Therefore it seems that its occurrence on the South side is a geological reality, rather than a human-caused anomaly (e.g. prehispanic commerce). Hence it represents a new locality and a new kind of jadeitite with a higher-P different P-T-X-t trajectory, but most probably one formed by the same overall petrogenetical process and geodynamical event. It thus also presents an extra possibility for the geological provenancing of Mesoamerican artefacts in jade which, in fact, collectively reveal several distinct kinds of jade.

gems, jade, pyroxene jade, fei cui, jadeite, dyed jade, treated jade, dyed jade, dyed and impregnated jadeite, b-jade

JADEITE JADE — Beads of an unusual color: An attractive necklace of predominantly brown-and-white (with lesser amounts of green) variegated beads (figure 10), which a client purchased recently in Tucson, was submitted to the East Coast lab for identification. We identified the beads as jadeite on the basis of standard gemological testing. Although many jadeite boulders have a brown outer layer (or “skin”; see, e.g., figure 6 of Winter 1995 Gem News, p. 278), where the color is due to staining by an iron compound, we do not recall ever having seen beads with this agate-like appearance. Some years ago, we encountered solid-color brown jadeite cabochons that we believed were the result of such natural staining. More recently we have seen jade of a fairly uniform brown color that appeared to be the result of some type of dyeing process. However, the variegated color of these beads indicates natural color. The fact that a number of the beads in the necklace were banded with grayish green jadeite further supports the conclusion that the color was probably natural and that the beads were cut from near the outside layer of a naturally stained jadeite boulder. Of the beads that we tested, all exhibited a 437 nm iron line and spot refractive index values within the normal published range for jadeite (about 1.66). For the most part, the beads were inert to both long- and short-wave ultraviolet radiation. The attractive brown-and-white variegated color suggests that these beads had not been subjected to bleaching and impregnation, since the brown veining would most likely be removed during such treatment. Infrared spectroscopy on a few of the beads confirmed that they were not polymer impregnated. [Figure 11. The green spherules in this polymer-filled cavity in a jadeite bangle make the filler much less conspicuous. Note also the many gas bubbles in the polymer. Magnified 25×.]