gems, corundum, treatments.6

Stephan and Müller examine methods for identifying heat treatment in corundum, with particular emphasis on ruby and sapphire. The article reviews the effects of heating on internal features and gemological properties and discusses the diagnostic evidence that can distinguish heated from unheated stones. Microscopic criteria include changes to mineral inclusions, healed fissures, altered growth structures, and other heat-related features, while spectroscopic and analytical methods provide additional evidence where microscopy alone is inconclusive. The authors consider the difficulties created by different heating temperatures, treatment conditions, and starting materials, since some treatments produce conspicuous alteration whereas others leave only subtle indications. The study emphasizes the need to combine microscopic observation with appropriate instrumental methods when determining whether a ruby or sapphire has undergone heat treatment.

gems, corundum, treatments.6

Lind provides an introduction to the treatment of gem corundum, outlining the principal methods used to modify the appearance of ruby and sapphire and the gemological problems associated with their identification. Particular attention is given to heat treatment, which may alter color and clarity, as well as treatments involving the introduction of foreign substances into fissures and other procedures intended to improve a stone’s appearance. The article places these techniques in the broader context of the gem trade and laboratory examination, emphasizing the distinction between natural characteristics and treatment-induced changes. It also introduces the diagnostic approaches used to recognize treated corundum, including microscopic observation and instrumental analysis, and stresses the importance of correct identification and disclosure of treatments.

gems, archaeology, archaeogemology, Russia, Central Asia

Cultural change in the “barbarian” world of the North Pontic region from the 3rd century bc to the mid-3rd century ad was not a special field of interest for ancient authors. Classical narratives only contain information about certain manifestations of such processes. In Russia, interest in studying the cultural changes that took place in the steppes of Eastern Europe in Antiquity appeared in the early 18th century, in connection with the accession of new territories to the East and West. The core of the cultural-historical model, which took shape and then developed in Russian historical research, was the idea of a constantly changing succession of peoples in the North Pontic region and of the historical role of this region as a buffer zone between East and West. On this basis, an aetiological myth of the Russian Empire took root, justifying its impressive size, its length along the meta-geographical axis of Eurasia and its historic role in the destiny of Europe. This concept assumed its definitive form in the early 20th century in the works of Mikhail Rostovtsev.

gems, jade, jadeite, fei cui, nephrite, China, Burma, Kazakhstan

The mineral chemistry composition and structural characteristics of jadeite from Burma, Kazakhstan, and Russia were studied by gemological methods, thin-section analysis, and electron probe analysis. The results on mineral chemical composition show that the contents of SiO₂, Al₂O₃, and Na₂O vary among samples: jadeite from Burma closely approaches the theoretical composition of pure jadeite, while samples from Kazakhstan and Russia deviate from this ideal. Burmese jadeite is characterized by the highest jadeite content and relatively lower amounts of albite and chromite. Jadeite from Kazakhstan contains a more balanced mixture of jadeite and omphacite, along with minor albite and chromite. Russian jadeite shows a chemical composition that transitions toward omphacite. Texturally, Burmese jadeite displays crystalloblastic texture along with partial metasomatic and dynamic metamorphic textures. The jadeite from Kazakhstan exhibits more complex textures, indicative of a strong geological overprint in a later phase. Russian jadeite shows crystalloblastic and partially crystalloblastic textures, reflecting a weaker degree of dynamic metamorphism. The jadeite deposits are multistage in nature: Burmese jadeite formed through two stages, omphacite in Kazakhstan formed through two stages, and Russian jadeite formed through three distinct stages. These metallogenic stages play a significant role in shaping the texture and structure of jadeite from each locality.

gems, diamond, inclusions

With its first-ever dedicated session and with the sponsorship of the Gemological Institute of America (GIA), gemology made significant progress towards recognition as a formal sci- ence by the mainstream geo-sciences community during this fall’s Geological Association of America’s (GSA) historic 125th Anniversary Annual meeting held October 27-30, 2013, in Denver, Colorado.

gems, archaeology, archaeogemology, Greece, Greek, Rome

gems, jade, jadeite, fei cui, Mesoamerica, Mexico, Guatemala, Costa Rica, Mayans, Olmecs, Aztecs, archaeology, history, archaeogemology, Sahagun, codices, codex

This thesis examines the illustrations of jade in Book XI of the twelve volume, sixteenth century Colonial Mexican manuscript, The Florentine Codex, or the Historia General de las Cosas de Nueva España. The book, a project led by Franciscan monk, Bernardino de Sahagún, records the Nahua world. These pictures of jade do not appear similar to most of the images contained within Book XI, as these are uncolored and use a different model to depict jade. By examining the individual elements of these pictures and the models used for this book and its illustrations, the jade images present a unique insight into the role of jade and stone in sixteenth-century Mexico. Sahagún was commissioned by the Franciscan Order to create a manuscript that could be used as a dictionary to aid the friars in communication and religious conversion with the native population of Central Mexico. He used native assistants trained at the mendicant school in Tlatelolco, where he had taught. By the end of the project, Sahagún was facing pressure from Spanish church and royal officials to end his research on the Nahua culture due to its recording of a pagan religion. The project was hurried and some illustrations had to be rushed. These jade illustrations show the effects of the rush. The artists had to create images that depicted the stone’s appearance without paint. They achieved this task by relying on the pre-Hispanic pictorial tradition. By depicting each jade stone’s appearance in symbolic forms, the illustrators represented both the stone’s physical appearance and metaphorical associations. The three jades—quetzalitztli, quetzalchalchiuitl, and chalchiuitl—distinguish how Nahua society valued differing characteristics of these stones. Importantly, the color of these stones created value and symbolic significance. The illustrations of jade provide a window into the sixteenth-century Aztec epistemology of color. The artists also used previous models from earlier and contemporary natural histories. By combining European and pre-Hispanic pictorial traditions, the illustrators create unique works that aligns best with Sahagún’s goal to produce a book for friars to understand the vocabulary of the native population. These illustrations of jade should be considered as a third text to the Spanish and transliterated Nahuatl, as they best reveal jade’s place within Nahua culture and how metaphors were created and used in Nahua rhetoric.

gems, magical gems, history of gemology, ancient gems, gem lore, gems and healing, medicinal use

Whether called emerald, jasper, agate, onyx, or anthracite… stones have a long history and, since Antiquity, have fired the imagination, nourishing beliefs, legends, and superstitions. Considered to be inhabited by sacred powers, they protect against accidents, envy, and witchcraft; they grant invisibility and the gift of tongues; they help fulfill wishes, predict the future, enhance memory, and cure illnesses… As for treatment, it may be done through application or rubbing, by grinding into powder to make a potion, or by wearing as a bracelet, ring, or pendant. Continuing his work on the supernatural, Claude Lecouteux, in this richly illustrated dictionary, has consulted many lapidaries—pagan, Christian, Gnostic…—and thus offers us a masterful synthesis at the crossroads of the history of mentalities, religions, and mysticism.

gems, jade, jadeite, fei cui, Mesoamerica, Mexico, Guatemala, Costa Rica, Mayans, Olmecs, Aztecs, archaeology, history, archaeogemology, Pre-Columbian jade; Costa Rica; Maya; exchange; iconography, lapidary

This volume, the third in a series of catalogues of Pre-Columbian art at Dumbarton Oaks, presents the outstanding collection of Aztec, Mixtec, Zapotec, Teotihuacan, and Classic Veracruz sculpture, jewelry, and painting. Four leading scholars present essays on the ancient art and archaeology of Mexico’s Central Highlands, Southwestern Highlands, and Gulf Lowlands as well as extensive catalogue entries of over one hundred objects of jade, shell, fine ceramics, wood, and other materials. The catalogue is richly illustrated with color plates, comparative illustrations, and diagrams presented as black-and-white figures. This catalogue will be an important and enduring reference for scholars and students, as well as an attractive volume for admirers of Pre-Columbian art.

gems, early lapidaries, early gemology, early mineralogy, Albertus Magnus, Philippe de Thaon, Jean de Mandeville, Middle Ages, medieval, medicine, Bible, magic, symbolism, beastiary

Treatises on precious stones, lapidaries catalogue and describe gems, then present their medicinal and magical virtues. The emerald heals vision; the sapphire enables escape from prison; the diamond, like the sapphire, is the stone of love; the carbuncle, which is born in the head of the dragon, shines with a dazzling brilliance, and so on. From the lapidary of Philippe de Thaon to that of Jean de Mandeville, these little-known texts open a window into the world of the marvelous, while shedding light on medieval encyclopedism. These treatises on precious stones present the inventory of the jewels and their medical and magical qualities. This volume gives the translation of five treatises dating from the 12th to the 14th century, thus giving access to these difficult texts so that their importance for the history of science and for social history of mentalities may be appreciated.