gems, corundum, France.12, ancient jewelry, Roman jewelry, Sri Lanka.

A second- to third-century CE necklace set with 14 sapphires was accidentally discovered in Lugdunum (present-day Lyon), France, in the mid-nineteenth century. It is part of the Trésor des Lazaristes now exhibited at the Lugdunum Museum in Lyon. All the sapphires are drilled lenticular beads of dark blue colour with estimated weights of 0.3–0.7 ct. UV-Vis-NIR spectroscopy indicated that 13 of the sapphires are basalt related, while one is of metamorphic origin. The inclusion features of the latter stone are consistent with those of sapphires from Sri Lanka. Because basalt-related sapphires from different deposits share very similar characteristics, their geographic origin cannot currently be determined. However, the proximity of the discovery site to known basalt-related sapphire occurrences in the Massif Central of France suggests a local origin.

gems, jade, pyroxene jade, fei cui, Burma, China, Hetian yu, Chinese jade, nephrite, yu, Guatemala, New Zealand, Japan, Russia, Kazakhstan, Canada, USA, Burma, Myanmar

At its core, any nomenclature system is a means of classification, a way to create logical categories that can be used to educate others. Like a garden, nomenclature systems require regular maintenance to remove overgrowth and “deadwood”. Nomenclature evolves naturally over time as it reflects the current state of knowledge. As understanding deepens, we often discover that items once thought to belong to one category more properly fit into another. At that point, we face a choice: move the item to the category that best represents it, or allow it to remain where it is as an exception. Every nomenclature system has these exceptions. This CIBJO guide examines one such case with jade, where mineral species names may have been improperly applied to gem materials that are actually rocks. This is not a purely academic exercise as financial costs may apply as a real consequence in a world where third-party verification of gem materials is a requirement, i.e., gem testing costs that involve the non-destructive analyses of rocks can be prohibitive, particularly at the low-value end. CIBJO takes no official position on this question. We recognize that many parties, particularly in China and across the East, consider the replacement of the terms/names jadeite, omphacite, and kosmochlor with the collective term/name fei cuì to be consistent with modern gemmological practice. Accordingly, they see no deception in marketing a gem whose constituent minerals are intimately intergrown under this unified term, a tradition that dates back to the early 1700s. At the same time, CIBJO acknowledges that traders, gemmologists, and consumers may prefer to divide pyroxene jade into its individual mineral components. CIBJO remains neutral on these differing approaches and accepts that variations in practice may exist between regions and that neither approach should be considered an unfair trade practice. There are sound reasons why nomenclature cannot, and should not, be expected to be identical everywhere. Each culture uses language to describe the world in its own way. The issue of ‘yù’ versus ‘jade’ illustrates this clearly: the two words carry distinct meanings, and neither has an exact equivalent in the other language. The proliferation of different languages and dialects reflects the diversity of human cultures. Nomenclature, therefore, inevitably carries a cultural dimension and must accommodate meaningful regional and linguistic differences where they arise. In the pages that follow, we aim to present this complex subject logically and consistently, bearing these principles in mind. The discussion represents the outcome of extensive dialogue among representatives from around the world. Jade is a human treasure. It is our hope that this guide will foster greater understanding of this remarkable natural canvas, beloved by jeweller and carver alike.

gems, beryl, emerald, Afghanistan, anthropology, Pakistan, Central Asia, Swat

An emerald from the late Hellenistic (or early Roman) period and another emerald from the end of the Middle Ages, both set in small rings, were studied using non-destructive methods. Their microscopic, spectroscopic and chemical characteristics are consistent with those of emeralds from the Swat Valley, Pakistan. This suggests that Swat Valley emeralds may have been more common in ancient jewellery than previously thought. This study highlights the importance of combining gemmological analytical techniques with archaeology to draw more reliable conclusions about the origins of historical gemstones.

gems, corundum, treatments.4, Sri Lanka.12, Madagascar.12, heat treatment, FTIR

This study examines sapphires naturally enriched in high-field-strength elements (HFSE) from metamorphic origins in Sri Lanka and Madagascar. These sapphires display distinctive chemical inhomogeneities and microscopic growth features, as well as variable FTIR spectra, often including a broad absorption band near 3300 cm–1. Some of the studied samples also show FTIR spectral characteristics and short-wave UV luminescence typically associated with heat-treated stones, although all were unheated. Our findings demonstrate that commonly used indicators—such as specific FTIR band patterns (mainly the 3309 cm–1 triplet) and chalky bluish white short-wave UV fluorescence—are not always reliable for identifying heat treatment. Accurate distinction between heated and unheated sapphires requires detailed microscopic examination combined with advanced trace-element analysis and spectroscopic techniques, including Raman micro-spectroscopy of inclusions such as zircon, goethite and diaspore.

gems, history of gemology,

Many important works of ancient literature have been translated many times over the centuries, perhaps none more so than Pliny the Elder's Natural History. Because classical writers did not follow conventions of objectivity or citation remotely similar to modern standards, understanding the literary context is important when trying to extract factual information. The perspective of a translator also shapes how modern readers interpret an elusive original meaning. Older translations are well known for distorting the meaning of a word or passage when the text is unclear. Translators sometimes imposed their own contemporary knowledge on the past-knowingly or not. This was especially common when they lacked subject expertise, misread corrupt (damaged) texts, or failed to grasp the literary genre, for example, interpreting poetic rhetoric as an objective description of physical things, as in technical writing. The task becomes more difficult when ancient words have no direct equivalents in modern languages. The following essay explores some of the challenges of technical writing about gems from the Hellenistic to Roman periods (323 BCE to-2nd century CE), with a focus on Book 37 of Pliny's Natural History, written in the 70s CE. It contains the richest vocabulary in classical literature for describing gemstones, including their names, colours, and visual properties. Although these terms do not always correspond with modern gemmological classifications, there are notable overlaps that can help identify some minerals whose identity might otherwise remain unclear.

gems, photomicrography, inclusions, quartz, chalcedony, agate

Throughout the history of gemology, quartz has been a main target of gemological microscopists. A detailed study of the wide variety of inclusions in quartz is as complex an earth-science related mental exercise as any gemologist would ever undertake. This is not surprising, as quartz occurs in a wider range of geologic environments than any other mineral species, and the inclusions it holds testify to this. The photomicrographs, pictured here with this study, provide the reader only a glimpse at the micro-world of quartz beyond rutile.

gems, gem trade, gem appraisal, jewelry appraisal, valuations, history of gemology

This article is a brief survey of the historical methods of describing and assessing the quality of coloured gemstones, tracing these from ancient times to the end of the 18th century. Examining historical texts and inventories reveals how features and flaws of gemstones were observed and used to determine their value. This article considers various historical periods, including the ancient world, the medieval Muslim world, early India, and medieval Europe, highlighting the changing criteria and expertise involved in gem judgement. This study demonstrates the historical depth of gem connoisseurship and its influence on modern gem assessment practices.

gems, gemology, history of gemology, gem testing, Great Britain, FGA, London

In Gems and the New Science, Michael Bycroft argues that gems were connected to major developments in the “new science” between the sixteenth and nineteenth centuries. As he explains, precious and semiprecious stones were at the center of dramatic shifts in natural knowledge in early modern Europe. They were used to investigate luminescence, electricity, combustion, chemical composition, and more. They were collected by naturalists; measured by mathematicians; and rubbed, burned, and dissolved by experimental philosophers. This led to the demise of the traditional way of classifying gems—which grouped them by transparency, color, and locality—and the turn to density, refraction, chemistry, and crystallography as more reliable guides for sorting these substances. The science of gems shows that material evaluation was as important as material production in the history of science. It also shows the value of seeing science as the product of the interaction between different material worlds. The book begins by bringing these insights to bear on five themes of the Scientific Revolution. Each of the subsequent chapters deals with a major episode in early modern science, from the expansion of natural history in the sixteenth century to the emergence of applied science early in the nineteenth century. This important work is not only the first book-length history of the science of gems but also a fresh interpretation of the Scientific Revolution and an argument for using a new form of materialism to understand the evolution of science.

gems, geology

This book is basically a retrospective of the writings/musings of John Saul, the noted geologist who discovered the John Saul ruby mine in Kenya. These essays touch on the great questions of Origins. The human adventure began when people first started to share complex ideas. A very early set of shared ideas provided a reasoned scheme that was both religious and scientific that would enable souls to take the Milky Way to the domain of the immortal gods. Other essays present cancer as originating when damaged tissues lose control over individual cells. Liberated cells multiply and may vary in ways that are incompatible with the functioning of multi-celled creatures, of humans in particular. Cancer first emerged during the Cambrian Explosion itself. Four essays discuss the survival of deep terrestrial impact-scars akin to those on the Moon, but far less easy to see. Such scars provide our planet's initial conditions. Fractures on the rim-zones of the scars guide plate tectonics and the deposition of minerals, and are implicated in at least one mass extinction.This book touches on little-discussed aspects of prehistory, history, the explosion of life during the late Precambrian, cancer research, and regional geology. Saul's writings and ideas represent some of the most original in the field of gemology, tying together not just the origins of gems, but the origins of human civilization itself. Highly recommended!

gems, tourmaline, cuprian tourmaline, tourmaline heat treatment, Paraíba tourmaline, Brazil, Nigeria, Mozambique

Determining the geographic origin of Cu-bearing tourmaline poses a significant challenge in gemmology, particularly when traditional microscopic methods yield inconclusive results. This study applies a combined analytical and computational approach using 469 gem-quality samples from Brazil, Mozambique, and Nigeria. A total of 57 elements (from Li to U) were quantified using full-mass-spectrum LA-ICP-TOF-MS. The high-dimensional elemental dataset was reduced to interpretable 2D maps using non-linear unsupervised machine-learning algorithms, including t-distributed stochastic neighbour embedding (t-SNE) and uniform manifold approximation and projection (UMAP). These methods successfully identified complex patterns and distinct subgroups, revealing compositional similarities not captured by traditional linear approaches. The resulting clusters provided a clear framework for geographic origin determination of unknown samples. Elemental signatures of key elements (i.e. Na, Ca, Li, Ti, Fe, Mn, Cu, Ga, Sr, La, and Pb) highlighted their influence on clustering and related geochemical variations to colour and geographic origin. Unsupervised machine-learning algorithms do not rely on predefined origin labels. This reduces errors caused by uncertain origin information and helps reveal statistical outliers that may point to new or undocumented sources. By integrating colour information with compositional clustering, the method also provides a possible framework for identifying heat treatment in high-clarity stones.