gems, alexandrite, emerald, intergrowth, phenakite

Describes polished intergrowths of alexandrite and emerald, reportedly found in Russia, and documents the identification and treatment features of a representative specimen. Several translucent to partly transparent cabochons and slabs weighing 6–25 ct appeared relatively homogeneous bluish green in daylight. Under incandescent illumination, however, portions changed to reddish purple while other areas retained their bluish green colour. A triangular 12.17 ct cabochon was examined in detail. Approximately 80% showed a distinct colour change, whereas the remaining 20% was nonphenomenal. Spot refractive-index readings of approximately 1.75 and 1.58 respectively supported identification of the two portions as alexandrite and emerald. The alexandrite displayed weak-to-moderate red luminescence under long-wave ultraviolet radiation and weaker red emission under short-wave radiation; the emerald portion remained inert. Yellow fluorescence along fractures suggested the presence of a foreign filling substance. Reflectance Fourier-transform infrared spectroscopy confirmed the identities of both minerals. Transmission spectra from both portions contained strong absorption between 3100 and 2800 cm⁻¹, indicating substantial hydrocarbon material and suggesting oil treatment to improve appearance. Microscopic examination revealed dendritic residues resembling dried oil within numerous fractures, consistent with the infrared results and the yellow fluorescence. Prominent water-related infrared absorptions were interpreted as evidence of natural origin. Two additional cabochons contained alexandrite, emerald and phenakite, the latter forming a narrow white zone along an edge and identified through infrared spectroscopy in transmission and reflectance. Their alexandrite showed only weak colour change and was consequently considered less attractive than the principal specimen. The report relates these associations to documented occurrences of chrysoberyl, beryl and phenakite in the emerald deposits of Russia’s Ural Mountains, particularly within or near desilicated pegmatites. Variations in temperature and chemical composition, especially silica availability, are cited as possible controls on their relative development. Comparable intergrowths have also been produced synthetically, making analytical verification relevant. Attractive natural examples are described as rare, and their occurrence together in finished gems is especially unusual because the constituent minerals tend to separate during shaping. The note demonstrates how selective colour change, identification of the separate mineral regions and treatment detection together establish the character of an uncommon natural mineral intergrowth.

gems, beryl, Mozambique, Maria, alkali-carbonic solution, emerald, fluid inclusions, nahcolite

The compositions of fluid inclusions in emerald and quartz from the Maria deposit in Mozambique were investigated using microthermometric and Raman microprobe techniques. The inclusions in emerald belong to the Na–Ca–Mg–(HCO₃)⁻–(CO₃)²⁻–Cl–H₂O system and are saturated carbonic acid brines. Nahcolite is the primary daughter mineral phase observed, with average concentrations of 25 wt.% nahcolite and 5 wt.% NaCl. Additional daughter phases identified include Mg-calcite, magnesite, calcite, and aragonite. Many fluid inclusions show a necked-down morphology, with groups of nahcolite crystals often comprising up to ~50 vol.% of these inclusions. Zones rich in fluid inclusions containing numerous birefringent solids appear to be characteristic of emeralds from the Maria deposit. Estimated conditions for emerald formation are between 400 and 500 °C and pressures of 3 to 4 kbar.

gems, beryl, emerald, Afghanistan, Laghman

Emeralds from Laghman, Afghanistan. For many years, Afghanistan has supplied modest amounts of high-quality emeralds from mines in the Panjshir Valley (see, e.g., G. Bowersox et al., “Emeralds of the Panjshir Valley, Afghanistan,” Spring 1991 Gems & Gemology, pp. 26–39). Recently, emeralds have also been found to the southeast in Laghman Province, which is famous for gem-bearing pegmatite deposits of tourmaline, spodumene, aquamarine, and morganite. According to Dudley Blauwet (Dudley Blauwet Gems, Louisville, Colorado), there are two emerald localities—Lamonda and Korgun. At Lamonda, large (up to 3 × 4 cm) semitransparent crystals are produced, and associated minerals on some specimens suggest that these emeralds formed in a granitic pegmatite, rather than in hydrothermal veins as in the Panjshir Valley. At Korgun, about 4–5 kg of smaller crystals were reportedly produced last summer, some of which are gemmy and have saturated color. Syed Iftikhar Hussain (Syed Trading Co., Peshawar, Pakistan) had about 25 faceted emeralds from Laghman, with the largest weighing 1.39 ct. Most of the stones were lightly included and their green color showed moderate saturation.

gems, corundum, quality.10, ruby, sapphire, spinel, balas ruby, turquoise, beryl, emerald, pearl, diamond,

gems, beryl, emerald, analytical, PIXE

A large collection of emeralds of various occurrences has been analysed by PIXE/PIGE in view to establish a compositional database. Major elements (Be, Si, Al) and trace elements (Li, F, Na, Mg, Ca, Rb, Cs and transition metals) are determined using an external 3 MeV proton micro-beam. Elemental micro-mapping permits to select the useful provenance tracers. This database was applied to infer the origin of several ancient emeralds set on historical jewels.

gems, jade, ruby, sapphire, spinel, beryl, emerald, tourmaline

This gorgeous coffee table book is distinguished from many other gem books by providing both a visually stunning format as well as an in depth geological perspective. Over 370 gloriously colorful photographs of gems and painstaking descriptions of their creation within the earth's crust give you intimate knowledge of gems. Additional chapters cover jeweled treasures used by royalty, historically important jewels, and gemstone lore.

corundum, synthetic corundum.7, gems

The 1990s witnessed important developments in the commercial viability of gem-quality synthetic diamonds. Improvements in, and new applications for, existing synthesis pr ocesses in the production of colored stones such as ruby, sapphire, emerald, quartz, and alexandrite have had an impact as well. The development and commercialization of a variety of new synthetics and simulants, such as synthetic moissanite and flux-grown synthetic spinel, also played an important role in shaping the past decade for the gem and jewelry industry.

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

The periods of Roman and Byzantine domination of Egypt* saw high levels of mining and quarrying in the Eastern Desert. Large quantities of porphyry, granite, gneiss and diorite were quarried at a number of sites (e.g., Mons Porphyrites, Mons Claudianus, and Wadi Barud). There were numerous gold mines, the largest Byzantine example probably being Bir Umm Fawakhir in the Wadi Hammamat. It was also in the Late Roman and Byzantine period that the emeralds of the Eastern Desert began to be quarried on a fairly large scale in the Eastern Desert between Myos Hormos and Berenice, principally in the Sikait-Zubara region (fig. 1). Because of these activities and the trade-routes via Red Sea ports such as Myos Hormos and Berenice, the desert was dotted with roads, watch-towers, way-stations and hydreumata (fortified wells) which attest to the presence of troops.5 The Egyptian emerald mines, which were perhaps first worked as early as the Ptolemaic period (c.332–30 B.C.), are believed to have been one of only two sources of emeralds for Europe and Africa during the Greco-Roman period (the other being the Habachtal mines in Austria).6 Although an uncut emerald has been tentatively identified in a necklace from the Predynastic site of el-Kubaniya, immediately north of Aswan,? such gem-quality beryls do not appear to have been used regularly in Egyptian jewellery until the Roman period, when techniques for polishing the stones probably began to be introduced. The Egyptian mines continued to be exploited until at least the Middle Ages, when Arab writers document the appearance of larger, heavier stones from the Indian subcontinent. In the 16th c., the Spanish conquest of the New World resulted in the export of emeralds from Colombia and Brazil to Europe and Asia on a massive scale, finally eclipsing the trade in Egyptian emeralds. In more recent times, fine emeralds have also been mined in a number of other Old World countries, including Zimbabwe, Zambia, and Pakistan.

gems, general, antique gems, history

A scholarly edition of a popular early modern collection of magical and medicinal recipes traditionally attributed to the thirteenth-century Dominican philosopher and naturalist Albertus Magnus (Albert the Great), edited by Michael R. Best and Frank H. Brightman. The volume reproduces William Copland’s sixteenth-century English translation of The Book of Secrets, accompanied by The Marvels of the World, with an extensive introduction examining the texts’ origins, authorship, manuscript transmission, and relationships to medieval natural philosophy, astrology, medicine, and popular magic. The editors demonstrate that the collection is a compilation of materials from several sources rather than an authentic work of Albertus Magnus, although portions draw upon his genuine writings. The principal text is divided into sections describing the supposed virtues of herbs, stones, and animals, followed by a discussion of planetary influences. Of particular gemological interest is the section on stones [25–49], which attributes extraordinary powers to numerous minerals and gemstones, including diamond, emerald, sapphire, amethyst, topaz, crystal, jasper, onyx, magnetite, coral, and various obscure substances whose historical names cannot always be identified with modern mineral species. Individual stones are credited with abilities to confer courage, wisdom, love, invisibility, victory over enemies, protection from poison, and relief from disease. Magnetite is said to reveal marital infidelity or drive away thieves, while sapphire is associated with peace, purity, and protection from fear. The text frequently specifies the conditions under which stones must be worn or employed, reflecting the close association of medieval lapidary traditions with sympathetic magic, astrology, and religious symbolism. The section on herbs presents comparable recipes involving plants and their alleged supernatural properties, while the section on animals describes the supposed virtues of particular organs, bodily substances, and animal parts. The Marvels of the World [74–112] expands these traditions into a collection of magical experiments, illusions, remedies, and extraordinary phenomena, including recipes involving minerals, metals, plants, animals, fire, and chemical substances. The editors’ introduction places these writings within the broader history of European magical literature, tracing influences from classical authorities, Arabic scientific and occult traditions, medieval encyclopedias, and Renaissance popular culture. Particular attention is given to the distinction between the empirical study of nature and the belief that hidden properties could be manipulated through magical procedures. The edition includes historical woodcut illustrations, textual annotations, variant readings, a bibliography, and an index. It is an important source for understanding medieval and early modern beliefs concerning gemstones, the transmission of lapidary lore, and the complex relationship between natural history, medicine, astrology, and magic.

gems, inclusions, beryl, emerald

Mineral inclusions in emeralds from eleven gem-mining regions and a hydrothermally grown synthetic emerald were chemically analysed with the electron microprobe JEOL JXA-8600. Emerald occurrences in Australia, Brazil, Mozambique, Russia, Tanzania (Lake Manyara) and Zambia belong to 'schist type' deposits. The inclusions comprise micas, talc, pyrophyllite, chlorite, wollastonite, chromite, calcite, dolomite, Fe-oxide, apatite, quartz, pyrite, fluorite and plagioclase. The geological settings for Colombian, Nigerian and Sumbawanga (Tanzania) deposits resulted in related assemblages of solid inclusions in these emeralds (for example, chlorine-rich Al- glauconite, sphalerite, titanium-rich mica, anhydrite and beryllium minerals).