gems, garnet, andradite, demantoid, demantoid cat’s eye, Iran

During the Tucson gem show, two cabochons of cat’s-eye demantoid from Kerman Province, southern Iran, were presented to GIA personnel, prompting an update on mining and production at this locality. Based on firsthand visits to the site between early 2001 and November 2003, one contributor provided details on the deposit and the emergence of chatoyant demantoid. Previously described in the Spring 2002 Gem News International (p. 96), this Iranian demantoid occurs near 28°19′N, 57°45′E, between the villages of Bagha Borch and Soghan, about 150 km south of Jiroft. Travel from Tehran to Jiroft takes about 16 hours, often slowed by highway patrols aimed at curbing drug trafficking, followed by a three-hour drive on rough roads to reach the mining site. Located at roughly 1,500 m elevation, the area features several hand-dug tunnels and pits spread across 500 m², worked mainly between December and March by about 10 miners. The demantoid occurs in regionally metamorphosed asbestiform rocks, with garnets ranging from yellowish green to dark emerald green. While faceted stones up to 7 ct have been reported, most cut gems weigh around 0.7 ct. Additionally, dark green and orangy yellow nodules up to 3 g and translucent crystals up to 5 cm have been recovered. During the 2003–2004 season, approximately 20 kg of rough was extracted, of which 1.5 kg was facet-grade and around 200 g yielded stones over 2 ct with desirable color and clarity.

gems, beryl, emerald, Egypt, Cleopatra, early lapidaries

Emerald, a green transparent variety of beryl, was one of the most highly prized gemstones in antiquity. The earliest known emerald mine is located in the mountain valley of Wadi Sikait in Egypt's Eastern Desert, where mining probably began toward the end of the Ptolemaic period in the first century BC. Most of the mining activity, however, dates to the Roman and Byzantine periods, from the late first century BC through the sixth century AD. The Romans referred to emerald as smaragdus and named the Sikait region Mons Smaragdus or Emerald Mountain. An archaeological geology survey of Wadi Sikait was undertaken for the purpose of mapping the distribution of ancient mine workings, deducing the ancient mining methods, and describing the geological occurrence of emerald. It was found that emerald and other green beryls occur within the contact zone between phlogopite schist and intrusive quartz and pegmatite veins. The workings, which were excavated in the softer phlogopite schist with flat-edged chisels and pointed picks, are mostly shallow, open-cut trenches that follow the quartz/ pegmatite veins. Some workings continue as much as 100 m underground and are still largely unexplored. It is noteworthy that the geological occurrence of beryl in Wadi Sikait, the world's oldest emerald mine, is essentially the same as for the world's newest emerald discovery at Regal Ridge in Canada's Yukon Territory.

gems, early lapidaries, Chrétien de Troyes lapidary, magical properties, medicine, carbuncle, emerald, beryl, corundum, history.1

Ruhe examines Chrétien de Troyes’s apparently anomalous use of emerald in Yvain, ou Le Chevalier au lion, where the perilous fountain has a pierced emerald block supported by four rubies. Medieval lapidaries, following Marbode, consistently attribute to emerald the power to avert storms and restrain lust, yet in Chrétien’s narrative the emerald is associated with precisely the opposite effects: the fountain produces violent storms, Yvain falls into passionate love and later madness, and other traditional virtues of emerald—revealing hidden things, foretelling the future, promoting eloquence, curing illness, and increasing wealth—are likewise systematically inverted. Ruhe argues that this is deliberate rather than an error or faulty recollection by Chrétien. Elsewhere Chrétien employs precious stones in ways consistent with lapidary tradition; the crucial distinction here is that the emerald is not worn on the body as a beneficial talisman but incorporated into a magical site. Its inverted powers therefore contribute to Chrétien’s ironic distancing from the supernatural traditions surrounding the fountain and perhaps also to a critique of knightly excess. The study demonstrates how close attention to medieval lapidary traditions can reveal a sophisticated literary play on the supposed virtues of gemstones in Chrétien’s work.

gems, beryl, emerald, Egypt, Sikait, archaeology, ancient emerald mining

This study of five of the major emerald mining localities within the Sikait-Zubara region of Egypt’s Eastern Desert investigates the potential for provenancing emeralds both from specific countries and from specific ancient Egyptian mines. The gemmological examination of several samples from Sikait-Zubara and elsewhere indicates that much of the geochemical variation in world emeralds is mirrored within single grains of emerald tailings; there are, however, two sources of emerald that can be distinguished from those of Egypt: the Urals and Colombia. These observations provide the potential for investigations of the world emerald market during the time of operation of the Egyptian mines and also the detection of forgeries manufactured from New World emeralds. The analyses also contribute to the general debate concerning the validity of archaeological provenancing, suggesting firstly that analysis must study variation within single grains as well as between grains sampled from different regions, and secondly that purely geochemical definitions of ‘sources’ or ‘provenances’ do not necessarily provide ready-made solutions to archaeological problems concerning the spatial movement of raw materials and artefacts.

gems, beryl, emerald, Egypt, ancient gem trade, Sikait

Egypt's Eastern Desert has been one of the most isolated and under-explored regions in the country, its ruins, spanning more than 5,000 years of history, protected by its forbidding climate and mountainous terrain. Now, rapidly encroaching resorts and villas along the Red Sea coast, together with mass tourism and a burgeoning local population, have placed its ancient sites at great risk. One of the most popular tourist destinations is what travel brochures call the emerald city" in Wadi Sikait: hundreds of buildings, temples, graves, and mine shafts associated with the search for emeralds that began in Roman times and possibly earlier. Demand for these precious stones prompted the flowering of Sikait in the region called by the Romans Mons Smaragdus (Emerald Mountain). The ruins that tourists see today are what is left of a humming center of industrial activity, but we know little about the mining operations here and the people who worked and lived in this remote desert area. How large was the population? Where did the inhabitants acquire food, water, and mining tools? The need for answers to these questions, as well as the growing threat posed by unrestricted access by visitors, makes our mission--the proper documentation and preservation of sites like Sikait--of the utmost importance."

gems, beryl, emerald, Canada, Yukon

In September 1998, a significant emerald occurrence was discovered at Regal Ridge in the Finlayson Lake district of southeastern Yukon, within the Yukon–Tanana Terrane. The emeralds are hosted in quartz veins that intersect mica-rich layers of a shallowly dipping mica schist from the Upper Devonian Fire Lake mafic metavolcanic unit, near a mid-Cretaceous granitic pluton. Emeralds, including gem-quality green beryl crystals up to 4 cm, are found in tourmaline-rich alteration zones surrounding the veins. These zones also feature scheelite, minor sulfides, and ochreous surface oxidation. The emeralds contain an average of 3208 ppm Cr, indicating chromium as the main chromophore. Fluid inclusions show formation from a low-salinity (max 3 wt.% NaCl equivalent), isotopically homogeneous fluid that exchanged oxygen isotopes with host rocks (δ¹⁸O of emerald = 12.3–14.8‰; δD ≈ −58‰). Coexisting quartz and tourmaline indicate formation temperatures of ~365–498 °C, corresponding to depths of 3–7.7 km and pressures of 1.0–2.5 kbar. Be is interpreted to have originated from the adjacent granite (with low Be: 12–13.2 ppm), and Cr from the host schist (520 ppm). An ⁴⁰Ar/³⁹Ar age of 109 Ma from mica likely reflects the timing of emerald formation or cooling post-granite intrusion.

gems, inclusions, beryl, emerald, Tanzania

Mineral and fluid inclusions were investigated in Tanzanian emeralds sampled in the Lake Manyara and Sumbawanga deposits. Microthermometry and Raman microprobe analyses were applied for this study. Primary and pseudosecondary H₂O–CO₂ inclusions, with numerous daughter solid phases, are common in the emeralds from the Lake Manyara deposit. Magnesite, Mg-calcite, aragonite, dolomite, calcite, nahcolite, quartz, and chrysoberyl were identified as trapped solids in fluid inclusions. Similar mineral inclusions were also found in the emeralds themselves. The composition of the trapped fluid present at emerald growth is estimated to be a carbonic-rich solution with chloride content of about 6 wt% NaCl equivalent. The P–T conditions of emerald growth are as follows: T = 370–470 °C and P = 3.0–7.0 kbar. Mineral inclusions of phenakite, euclase, bertrandite, and helvite are common in the emeralds of the Sumbawanga deposit. CO₂-rich inclusions with an aqueous phase (usually below the detection limit), and CaCl₂-rich inclusions with salinity of up to 17 wt% NaCl equivalent, are related to emerald growth. The trapping of fluid inclusions postdates the growth of mineral inclusions. The P–T conditions of emerald growth are as follows: T = 220–300 °C and P = 0.7–3.0 kbar.

gems, corundum, history.1, diamond, beryl, emerald, India, Goa, Burma, Sri Lanka, Indian lapidary

Portuguese Asia, otherwise known as the Estado da Índia Oriental, has been far less studied than the Spanish empire in America, its counterpart in the Western hemisphere. It differed from that vast entity in that it was essentially a maritime trading operation held together by strategic territories, such as Goa, Ceylon, or Macau. For more than a century these afforded it control of much of the Indian Ocean. As Professor Winius shows, it was certainly the most peculiar and colourful operation that existed in the history of European expansion, even giving rise to a second, ‘shadow’ empire created by escapees and renegades from its royal administration. Some of these essays reflect on Portuguese involvement in other areas, notably the Atlantic, and the impact this had in the East, but their focus is on the Portuguese in South and Southeast Asia. They describe its nature and its rise and fall, from the first voyage of Vasco da Gama to its dismemberment by the Dutch in the mid-seventeenth century, and include studies on the jewel trade and on the Renaissance in Goa.

gems, beryl, aquamarine, emerald, garnet, grossular, tsavorite, pyrope-almandine, hematite, opal, quartz, amethyst, topaz, zircon, vesuvianite, spinel, ruby, sapphire, sphene, titanite

Gem-quality minerals such as emerald, ruby, sapphire, aquamarine, garnet, and amethyst have been found recently in Somaliland. The majority of the gemstones are derived from pegmatitic host rocks related to late granite intrusions within the Mozambique orogenic belt, which extends through the centre of Somaliland in an east-west zone. Where pegmatites cross-cut biotite and amphibole schists, emeralds may occur, whereas aquamarines are more common when pegmatites intersect migmatites and granite gneisses. Not all reported gemstones have been collected from known production sites, and minerals such as rubies, sapphires, opal, and pyrope or almandine garnet likely originate from a variety of rock types. Most gemstones are extracted from solid, unweathered rock using rudimentary recovery methods. The importance of gemstones in the Mozambique orogenic belt has already been recognized in Kenya, Tanzania, Sri Lanka, India, and Madagascar. The identification of this belt’s extension into Somaliland is therefore of considerable significance, suggesting untapped potential for a wide range of gemstone production, which remains to be fully assessed.

gems, beryl, emerald, natural, synthetic, PIXE, wurtzite, sphalerite, pyrite, phlogopite