inclusions, photomicrography, gems

De Goutière presents a brief photographic essay celebrating the visual interest of gemstone inclusions through three colour photomicrographs of two specimens. The emphasis is on the striking patterns revealed by microscopic observation and their resemblance to recognizable scenes or abstract compositions. The first photograph shows a thin film within a light green beryl crystal that has been ground to a thickness of 1 mm. Its intricate, multicoloured forms are likened to a tropical garden containing a palm tree and butterflies. Branching and fan-like details occupy a broad field of yellow, blue, green, and violet, with darker areas framing the composition. The comparison concerns the appearance of the photographed inclusion rather than the presence of biological material. The remaining two photographs depict unusual tubular inclusions in a 0.07 ct round brilliant-cut diamond. In one view, bright, angular, tube-like forms appear among the stone’s reflected facet patterns and several dark rounded features. The accompanying caption humorously compares their extraordinary configuration to uncontrolled laser drilling. A second photograph presents a pavilion view of the same diamond, revealing the network from another direction. Here the tubes form a conspicuous labyrinth of straight segments and sharp changes in direction against contrasting bright and dark areas. De Goutière characterizes the effect as natural abstract art, using the change of viewpoint to present a different composition within the same small gemstone. The editorial introduction places these photographs within an ongoing presentation of the author’s work with camera and microscope and frames the specimens as subjects created by nature. The contribution is descriptive and pictorial: it provides the host materials, the preparation thickness of the beryl, and the weight and cut of the diamond, but does not identify the thin film’s composition, explain the tubular inclusions’ formation, or supply magnification and illumination details. Its central purpose is to demonstrate the aesthetic possibilities of inclusions and the distinctive internal images that gem photomicrography can reveal.

gems

Backler criticizes inadequately researched jewellery valuations and sets out the knowledge, documentation, equipment, and ethical standards required for a defensible professional appraisal. She treats the valuation report as a legal document that must describe the object fully, substantiate its conclusions, and communicate clearly to both specialists and clients. Insurance valuations are distinguished from probate assessments: the former concern current replacement on a like-for-like basis, while the latter are described as assessments based on material values without workmanship, taxes, or commercial mark-ups. Reliable practice requires gemmological training, continuing education, suitable testing instruments, reference literature, current diamond and coloured-stone prices, and familiarity with precious-metal testing and markets. Appraisers must also understand exchange rates, inflation, import duties, taxation, labour costs, and the successive mark-ups affecting retail replacement. Detailed worksheets and retained records provide the evidence needed to explain conclusions, resolve later disputes, and support testimony in court. Backler condemns valuations altered to accommodate clients’ wishes and deliberate undervaluation intended to discredit competitors or secure goods cheaply. She emphasizes the client’s dependence on professional honesty and the obligation to disclose gemstone treatments, including oiling, glass filling, laser drilling, dyeing, impregnation, heating, and irradiation. Poor valuations can leave clients seriously underinsured, while incomplete descriptions impede identification and encourage disputes over alleged stone substitution. She recommends examination in the client’s presence where practicable and warns that cleaning can markedly change a jewel’s appearance. A case study contrasts a brief, inaccurate retail appraisal with a detailed replacement assessment of a diamond engagement ring and matching wedding band. The deficient report underestimated the principal diamond’s weight, assigned a substantially lower clarity grade, and was followed by an offer to purchase it cheaply. The fuller assessment records metal fineness and weight, construction, gemstone measurements, estimated weights, colour, clarity, fluorescence, finish, identifying marks, and condition. Editorial annotations by R.W. Hughes qualify several of Backler’s assertions. They stress that some treatments are difficult or impossible to detect, that observing an appraisal may introduce security problems and pressure to rush, and that distinctive inclusions or surface features can help establish identity before cleaning. The concluding editorial also cautions against condemning all retail appraisers and emphasizes specialization, practical experience, and candid acknowledgement of uncertainty. Both author and editor ultimately argue that trustworthy valuation depends on documented evidence, sustained professional competence, integrity, and recognition of the limits of one’s expertise.

corundum, inclusions.5, gems

corundum, inclusions.5, gems

gems, chrysoberyl, alexandrite, synthetic alexandrite, crystal growth, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), Tairus, Kyocera, flux growth, Czochralski, zone melting

Infrared spectroscopy provides a means to distinguish natural from synthetic alexandrites in the range 2000–4200 cm⁻¹, as determined by a study of spectra obtained from 15 natural and 28 synthetic alexandrites from a variety of sources. The technique is nondestructive and, with Fourier transform instrumentation, extremely rapid. It is especially useful for identifying stones that contain no distinguishing inclusions.

gems, chrysoberyl, alexandrite, Brazil, Hematita, Minas Gerais

Two characteristic mineral inclusions observed in the alexandrites from the recent discovery at Hematita in Minas Gerais, Brazil (see the article by K. Proctor in this issue], have been identified by means of detailed chemical analysis. Dr. Henry Hanni found inclusions of fluorite (figure 7) in one of the alexandrites, and Dr. Karl Schmetzer and Mr. Charles Schiffmann confirmed the identification of apatite (figure 8). Dr. Edward Gübelin initiated the study and followed it through to completion. This is the first time that fluorite has been recognized as a mineral inclusion in chrysoberyl.

corundum, inclusions.5, Umba sapphires, gems

New evidence of treatment in Umba sapphires. Any evidence that provides absolute proof that a sapphire has or has not been heat treated is always of value to gemologists. A recent investigation done by one of the Gem News editors (JIK), which was published in the Journal of Gemmology (Vol. 20, No. 7, 1987), showed just such evidence in the form of colored halos surrounding solid mineral inclusions in sapphires from Sri Lanka and Montana. The halos result from the heat-induced theft, by the sapphire host, of color-causing ions from the mineral inclusions. After reading the above-mentioned article, Dr. Henry A. Hänni of the University of Basel and the Swiss Foundation for the Research of Gemstones contacted Gem News and reported his discovery of similar internal diffusion halos surrounding tiny mineral inclusions in blue sapphire from the Umba River region in Tanzania, East Africa (figure 6). Dr. Hänni’s observation provides positive evidence that at least some of the sapphires from this locality are being heat treated.

chrysoberyl, alexandrite, synthetic alexandrite, gems

Reports the examination of an alexandrite whose internal characteristics made the determination of natural versus synthetic origin problematic. The authors describe the gemological and microscopic features used in reaching an identification, emphasizing the diagnostic significance of inclusions and growth structures and the difficulties that may arise when apparently natural-looking features occur in synthetic material. The study illustrates the need to evaluate the complete combination of internal, optical and other gemological properties rather than relying on a single diagnostic feature when separating natural alexandrite from its synthetic counterparts.

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

Three-phrase inclusions i n untreated natural color-less, yellow, and blue sapphires from Sri Lanka were found to consist of liquid and gaseous carbon diox-ide cis well as needle-like to tabular crystals of di-aspore. The identification of diaspore was accom-plished through the use of a microscope-mounted drill system and an improved version of the Gandolfi X-ray camera. Technical details for both methods are given. The conditions under which diaspore forms as a daughter mineral in corundum are briefly dis-cussed.

Corundum, ruby, Nepal.12, inclusions.5, gems

Bank and colleagues describe a high-quality faceted ruby reportedly from Nepal whose unusual growth structures and inclusions initially raised doubts about its natural origin. The 1.288 ct stone, cut as an approximately equilateral octagon measuring 6.00 × 6.00 × 4.15 mm, combined excellent transparency with a desirable red colour, contrasting with the predominantly cabochon-quality Nepalese material previously available. Routine measurements gave refractive indices of 1.770 and 1.762, birefringence of 0.008, density of 3.98 g/cm³, and the normal chromium absorption spectrum, properties compatible with both natural and synthetic ruby. Ultraviolet–visible spectrophotometry showed similarities to previously studied Nepalese corundum but lacked significant iron–titanium charge-transfer absorption in the red region, accounting for the absence of a purplish sapphire component. Immersion microscopy revealed a dark red centre, opposing near-colourless marginal zones, and broad alternating red and colourless bands parallel to the basal pinacoid. Boundaries associated with prism and dipyramidal growth formed angles of approximately 90° and 85° with the basal zoning. Although superficially comparable to nearly rectangular zoning in Ramaura synthetic ruby, these structures involved different crystallographic forms. Spindle-like growth features within the red centre also resembled structures encountered in flux-grown synthetics, while fine dust-like striations recalled inclusions in Kashan synthetic ruby. These similarities made straightforward microscopic classification unreliable. Electron microprobe examination of surface-reaching inclusions at the girdle and near the culet identified phlogopite, a mica already known in association with Nepalese ruby and pink and violet sapphire. Further microscopy disclosed feathers comprising irregular cavities and negative crystals containing liquid, two-phase fillings, and probable three-phase solid–liquid–gas inclusions. Some solid components displayed interference colours under crossed polarizers. These feathers could resemble residual flux in synthetic ruby, but comparable features had previously been recorded in lower-quality Nepalese specimens. Extremely thin fluid films, sometimes containing both liquid and gas, provided additional evidence of natural formation and showed interference colours under suitable illumination. The authors conclude that the combined presence of phlogopite, multiphase inclusions, and ultrafine fluid films establishes natural origin and confirms the reported Nepalese provenance. The case demonstrates how exceptional natural growth structures can imitate familiar synthetic features, requiring crystallographic interpretation, inclusion identification, and multiple complementary observations rather than reliance on superficial resemblance.