gems, emerald, beryl, inclusions, UV-Vis-NIR spectroscopy, history, origin, clarity enhancement, Colombia, Zambia, Brazil, Afghanistan, China, Pakistan, Russia, Zimbabwe, Sandawana, Nigeria, Tanzania, USA, North Carolina

Excellent summary of emerald inclusions and UV-Vis-NIR spectra from different origins and description of different emerald enhancements

gems, beryl, emerald, Colombia, Muzo, Chivor, Cosquez

Fantastic history of Colombia’s emerald mines, along with fine photos of emeralds in matrix and some cut stones and jewelry. A must have for emerald lovers.

gems, corundum, treatments.6

The association of ruby with treatments that result in an addition of glass to the final product began in 1984 with the appearance on the market of Thai origin rubies in which cavities had been filled with glass (Kane, 1984, Scarratt, et al., 1984) a treatment that had evolved into glass crack filling by 1987 (Hughes, 1987, Scarratt, 1987). In 1992 with the discovery of corundum deposits in the area of Mong Hsu, Burma (Myanmar) that required high temperature-flux heating regimes to bring the material to market the association of ruby treatments and glass was dramatically expanded (Hlaing, 1993, Kremkow, 1993, Laughter, 1993, Peretti, 1993, Smith, et al., 1994). Twenty years after the first association a new ruby-glass association a new form of glass fracture filling in ruby appeared on the market (GAAJ, 2004, Pardieu, 2005, Smith C.P., 2005, McClure, 2006). Pardieu (Pardieu, 2005) noted that “some terminology problems may occur about this treatment regarding to the “Lead Glass” definition as many different formulas can be used: Pure lead oxide, lead oxides mixed with silica or fluxes like borax can be encountered... Temperatures, parameters and result can be very different. Some specific studies will probably be done in the future regarding to this issue”. Pardieu (Pardieu, 2005) also witnessed the treatment procedure as performed in Chantaburi, Thailand by Master Burner Mahiton Thondisuk and reported that “the most suitable rubies for repair are stones with color potential and that are rich in fissures”. He stated further that “this new treatment is performed currently mostly on Andilamena rubies (Madagascar) on which Mr. Thondisuk has had extensive experience but any ruby material with fissures could be “repaired”. It is a multi step treatment involving simple heating and the use of different lead rich compounds to fill the fissures and cavities of the stones. If most of the “repaired” stones seen were large size stones, stones less than 1 carat have also been treated this way”. While Pardieu did allude to wide tracts of glass crossing the surface of examples he examined in 2004 – 5 until recently (early 2008) the material observed in laboratories1 had an equivalence to treatments applied to “clarity enhance” emeralds (with the use of resins and oils) and diamonds (glass) and therefore the terminology used was adapted from these, i.e., minor, moderate or significant clarity enhancement. In reality the vast majority fell into the significant clarity enhancement category although as McClure (McClure, 2006) points out “ the efficiency of the treatment is such that a single large fracture in an otherwise clean ruby could be made to “disappear” to the unaided eye exactly as filled fractures can be made to “disappear” in emeralds and diamonds. In fact, we have already seen several stones that fall into this category. Further and following stability tests laboratories within the Laboratory Manual Harmonization Committee (LMHC)2 added “Glass filler may be unstable to elevated temperatures and to chemical agents. Special care shall be taken when repairing jewelry items set with glass filled corundum. During jewelry repair the unmounting of such stones is recommended” to reports on these stones. During a meeting of the LMHC held October 18th -20th 2007 in New York City, Dr. Pornsawat Wathanakul (Scientific Advisor to the GIT member) reopened discussions on glass fracture filling in ruby. Several members had noted myriads of large gas bubbles within the newer material being submitted to their laboratories and that in many cases the glass was filling wide seams crossing facets and seemed to be accounting for an ever increasing volume of the finished product. Further, it was surmised from observation that the material was being held together by the glass, i.e. the glass acting in similar manner to an adhesive. Following discussions and an agreement that this treatment went beyond what might be regarded as a “fracture filling or clarity enhancement process”, the group decided to describe this (heavily treated) material as “ruby-glass composites” i on all future identification reports. Further on November 13th 2007 American Gem Laboratories (AGL) announced that they were changing their reporting policies with regards these stones (AGL, 2007) and indicated that their report wording henceforth would be Identification: Composite Ruby, Standard enhancement: Heat, and Additional enhancement: Lead-glass. They also indicated a further comment would be added -This ruby has been heavily treated using a high refractive index lead-glass to fill fractures and cavities,vastly improving the apparent clarity and potentially adding weight. The glass may be damaged by a variety of solvents. This paper describes several “rubies” treated with glass and experiments carried out at GIA Laboratory (Bangkok) and at GIA New York that demonstrate the LMHC assumption – that the stones are being ‘bonded together’ by glass. As an implication of these experiments and given that several gemstones (ruby, emerald and diamond being the most often cited but others including tourmaline and quartz being not uncommon) are “clarity enhanced” through the infusion of fractures with oils, resins and glass, the paper also introduces new (February 2008) nomenclature for describing stones that have been clarity enhanced and those that are clearly composites.

gems, beryl, emerald, Mughal emerald, Russia, Hermitage, St. Petersburg, historical emerald

In 1741 the Persian Nadir Shah presented 37 objects of Mogul treasures from his conquest of Delhi to Russia. Eighteen objects have remained in the collection of the State Hermitage Museum in St. Petersburg. A gemmological study of 3000 emeralds in 3 pitchers and a plate from the XVII c., carried out in September 2003 at the Hermitage Gold Room, revealed Colombia as the country of origin, due to a characteristic inclusion pattern caused by hydrothermal formation. The result confirmed gemmological testing done in 1984 by M. B. Chistyakova and is compared with emeralds from two other origins which were known since antiquity: Egypt and Habachtal in Austria. They were ruled out as possible Mogul sources, due to their different type of emerald formation and lack of regular production. The deposit of the Panjshir Valley in Afghanistan, discovered in 1976, which may coincide with the emerald deposit of Bactria, written about by Theophrastus and visited by Alexander the Great, was also ruled out. There is no evidence of mining between the IV c. BC and the 1970s, and there is no further written evidence available so far. Moreover, the inclusion picture of Afghan emeralds differs.

gems, ancient gems, glyptic, Egypt, history of gemology, history of mineralogy, archaeogemology, archaeology, beryl, emerald, Cleopatra

Egypt's ancient sites between the Nile Valley and the Red Sea. For thousands of years Egypt has crowded the Nile Valley and Delta. The Eastern Desert, however, has also played a crucial―though until now little understood―role in Egyptian history. Ancient inhabitants of the Nile Valley feared the desert, which they referred to as the Red Land, and were reluctant to venture there, yet they exploited the extensive mineral wealth of this region. They also profited from the valuable wares conveyed across the desert between the Nile and the Red Sea ports, which originated from Arabia, Africa, India, and elsewhere in the east. Based on twenty years of archaeological fieldwork conducted in the Eastern Desert, The Red Land reveals the cultural and historical richness of this little known and seldom visited area of Egypt. A range of important archaeological sites dating from Prehistoric to Byzantine times is explored here in text and illustrations. Among these ancient treasures are petroglyphs, cemeteries, fortified wells, gold and emerald mines, hard stone quarries, roads, forts, ports, and temples. With 250 photographs and fascinating artistic reconstructions based on the evidence on the ground, along with the latest research and accounts from ancient sources and modern travelers, the authors lead the reader into the remotest corners of the hauntingly beautiful Eastern Desert to discover the full story of the area’s human history.

gems, beryl, emerald, Norway

An emerald deposit at Byrud, in southern Norway, yielded significant quantities of crystals and gem rough in the late 19ᵗʰ and early 20ᵗʰ centuries. Complex multiphase inclusions in the emeralds consist of water, gaseous methane, halite, sylvite, calcite, and a sulfide assemblage (pyrrhotite, galena, and sphalerite). This sulfide assemblage makes it easy to distinguish Byrud emeralds from those from other localities with a binocular microscope. The chemical composition of Byrud emeralds is also characteristic: they are colored mostly by vanadium (up to 1 wt.% V₂O₃), and contain low sodium and magnesium (0.1 wt.% oxide or less). Moreover, the relative amounts of iron, magnesium, chromium, rubidium, and cesium appear to be diagnostic. Infrared absorption spectra show that they contain little water. Emeralds from the Byrud deposit are still occasionally recovered by hobbyist collectors from the mine dumps.

gems, general, properties

This is a comprehensive guide to the fascinating world of precious gems and ornamental stones. As well as the naturally occurring minerals that have long been prized as gemstones, such as diamonds, emeralds and rubies, the book covers 'organic gems', including pearls, amber and coral, and synthetic gems and stimulants, or imitations. There is an introductory section that examines the appeal of gemstones, the history and the popularity of collecting, the basic rock types, principles of crystal formation and physical properties, while the main encyclopedic section provides information on the origins and makeup of over 200 major stones, their properties and qualities, as well as major world sources. The latter sections of the book cover the cutting and finishing processes, the ways in which stones can be enhanced or 'improved' and offers pointers on starting a collection and exploring the subject in greater depth.

gems, Afghanistan, Panjshir Valley, beryl, emerald

Six years ago, Taliban chief Mullah Omar ordered the destruction of all non-Islamic art and tombs in Afghanistan, a campaign that devastated the country’s cultural heritage—from the monumental Buddhas of Bamiyan to countless small artifacts—leaving perhaps only a third of the Kabul National Museum’s collection intact. It seemed once again that Afghanistan’s archaeological legacy was fated to be lost amid its long history of tribal conflict and instability. Yet the extraordinary gold, glass, stone, and ivory objects in the current exhibition tell another story. Two-thirds of the objects are jewellery or other precious items, and most are the gold ornaments from Tilia Tepe, believed lost but now astonishingly returned to public view. Many of the 200 works on display—spanning 2,500 years of Afghanistan’s history—are being shown to a Western audience for the first time. Most have secure provenance, with sites like Fullol, Ai-Khanoum, Tilia Tepe, and Begram well represented. For a jewellery historian, a common frustration in such exhibitions is the inability to examine pieces under a microscope; one must make do with a small close-focus monocular, which—despite amusing nearby visitors—allows for enough magnification at 45 cm to observe some construction and decorative details. The technical observations that follow are based on these less-than-ideal viewing conditions, compounded by the crowded exhibition space where many of the gold objects had to be viewed while obstructing a narrow, slow-moving line of visitors. One wonders what the average visitor learns in such a setting, especially when labels offer little more than the word “ring.”

gems, beryl, emerald, emerald fillers, emerald oiling, emerald treatments

Researchers treated 128 emeralds with nine emerald fillers—Araldite 6010, cedarwood oil, paraffin oil, unhardened and surface-hardened Opticon, a mixture of cedarwood oil and Canada balsam, surface-hardened Norland Optical Adhesive 65, and the solid fillers Gematrat and Permasafe—and then exposed them (along with 14 unfilled emeralds) to common conditions of wear and cleaning. All emeralds were held for about six years, and most were then subjected to one of the following durability tests: exposure to long-wave UV radiation (a component of sunlight), to mild heat and incandescent light in a display case, to five chill-thaw cycles, and to a desiccation environment; ultrasonic cleaning with either warm water or BCR; and cleaning with steam or mild chemical solvents. Changes were evident in about 35% of the filled emeralds after the mild exposure tests (i.e., time, UV radiation, display case); those with liquid fillers were especially susceptible. The desiccation environment made fissures visible in a majority of emeralds. Hard fillers damaged their host emeralds by expanding cracks during durability testing, while chill-thaw cycling extended cracks in both filled and unfilled emeralds. Emeralds with liquid fillers were most susceptible to appearance changes due to ultrasonic cleaning and exposure to ethanol or acetone. Some observations on the effectiveness of different fillers on emerald appearance are also provided.

corundum, ruby, sapphire, synthetic corundum.7, treatments.6, color.4, properties.3, assembled stones.8, gems, pearls, emerald, gemology

Since it was first published in 1962 ‘Gems’, written by Robert Webster and revised in its fourth edition by Basil Anderson, has become universally recognised as the most comprehensive and authoritative treatise on gem materials in the English language. In this fifth edition, edited by Peter Read, the forty chapters, appendices and tables have been revised by fifteen gemmologists chosen for their expertise in the relevant sections. Aimed at the professional jeweller and student gemmologist, Gems also caters for the collector of gems and the layperson who is interested in precious stones.