gems, corundum, quality.10, crown jewels, Austrian crown jewels, spinel, diamond, pearl, beryl, emerald, ivory

This book details the Vienna Imperial Treasury, the only preserved collection of medieval crown jewels in the world. The crowns, gowns and jewelry on display cover the Middle Ages in Europe – roughly the years 500 to 1500 AD. Beautifully illustrated, but sadly only available in softcover.

gems, corundum, sapphire, synthetic corundum.7, beryl, emerald

Gagan Choudhary FGA, deputy director of Gem Testing Laboratory Jaipur, describes various types of fake gem rough that has passed his desk in recent months, including mica rock presented as emerald rough, cubic zirconia and topaz fashioned as diamond octahedrons, and synthetic quartz mimicking aquamarine.

gems, jewelry, diamond, history of jewelry, emerald, pearl, ruby, topaz, imperial topaz, Brazil, amethyst, glyptic

Joao Távora Magalhães, Sotheby’s: The story of this book—and of the exhibition that first accompanied it in Lisbon—began with a chance visit to S.J. Phillips on New Bond Street in October 2016. Drawn in by an intriguing Instagram post, I stepped into this legendary gallery hoping to see some fine jewels. What I found, quietly displayed in the back room, was a remarkable group of pieces whose color and energy were both astonishing and deeply familiar to my Portuguese eyes. In that moment, I knew this extraordinary collection had to be brought to Lisbon for public display. A quick conversation with Francis, Jonathan, and Nicolas Norton, the partners at S.J. Phillips, and a visit from our ever-supportive Chairman of Sotheby’s Asia, Patti Wong, set everything in motion. Portugal, in the context of European arts, has made an indelible mark by absorbing global influences from the many territories with which it has long been associated, creating a distinctively national style that found its finest expression in the Decorative Arts. The S.J. Phillips Collection of Portuguese jewels—centered on 18th-century masterpieces—perfectly embodies a moment of immense richness in Portuguese art, when Lisbon was receiving vast quantities of gold, diamonds, and minerals from Brazil. There, these treasures merged with the latest European artistic trends under the patronage of the great King Dom João V. Diana Scarisbrick, the foremost authority on historic jewelry, not only documents this pivotal period but also traces the development of this sophisticated art form in its entirety. Through her words and insights, we hope to bring greater international recognition to Portuguese jewels. Sotheby’s and S.J. Phillips have been neighbors on Bond Street—the heart of the art and antiques world—for a century, enjoying a warm, fruitful, and always mutually enriching relationship. It is a deep pleasure to mark this centennial friendship with this book. On a personal note, I offer my heartfelt thanks and admiration to Francis, Jonathan, and Nicolas Norton for assembling this exquisite collection and for allowing Sotheby’s and me to share in its story.

corundum, chemistry.2, gems

The purpose of this work is to investigate the crystal growth parameters necessary or sufficient to obtain a crystal specifically of gem quality. We assume adequate chemistry is available. First, nucleation must occur with only a limited number of nuclei, otherwise too many crystals will be produced, and they will be too small to be faceted into a gem. Two growth mechanisms are readily documented for gems: Most commonly there is slow growth, driven by a spiral growth mechanism, leading to large single individuals. There are only a few examples of fast growth leading to gem-quality edifices: examples include ‘‘gota de aceite’’ Colombian emerald or the dendritic ‘‘pseudo cube’’ for gem diamonds. We have not documented the intermediate conditions between these two extremes in the Sunagawa diagram, which would correspond to 2D nucleation growth. The presence of inclusions is to be limited to desirable ones. Thus, in general, a good stability of the growth interface is the best guarantee of good clarity in the final gem. As for the interface, in general, growth conditions must be relatively stable over the period necessary to achieve growth. Perhaps surprisingly, it has become well documented that gem-quality near-colorless diamonds may have experienced quite a complex growth history. Therefore, the term stability has to be re-defined for each system producing a given gem. The length of time it takes to achieve crystallization of the gem has rarely been studied or estimated. Scientific evidence from experimental petrology and the growth of synthetic gems indicates that it does not take millions of years to grow a gem, but that this exercise may be achieved in a week to, arguably, a few years at the most. Available free space to grow does not appear always necessary, but it helps. Otherwise deformation, inclusions, and other negative effects may occur. Finally, no dramatic post-growth events, such as fracturing or etching, should affect the gem crystal.

gems, early lapidaries, Albertus Magnus, French lapidaries, magical properties, medicine

The Middle Ages believed in the powers of precious stones: their medicinal and magical virtues were recorded in encyclopedic treatises known as lapidaries. This knowledge, inherited from Antiquity, endured for centuries: diamond grants invincibility; sapphire frees prisoners; emerald heals vision problems; amethyst protects against drunkenness; hematite stops bleeding, and so on. The powers attributed to stones operate by analogy—a mode of thinking that prevailed throughout the medieval period. This anthology of medieval lapidaries offers, for the first time, a bilingual edition of these long-dismissed and still largely unknown texts, with a selection of excerpts in Old and Middle French accompanied by their translation.

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

Stones or gems considered highly valuable, chalchihuitl and xihuitl (jades and emeralds), appear many times in the codices as metaphors for that which is beautiful and precious. In Nahua songs and poems, the chalchihuitl, a precious reality, is identified with the heart and even with the human person. Reference to the transience and passing of rulers and of all that exists is reiterated again and again through the metaphor of jade.

gems, agate

Jade is the eighth in a series of gem books written and photographed by Fred Ward and Charlotte Ward, who updated this edition. Each book Rubies and Sapphires, Emeralds, Diamonds, Opals, Pearls, Gem Care, and Phenomenal Gems is part of a continuing global search into the history, geology, lore, and sources of these priceless treasures. Mr. Ward personally visited the sites and artifacts displayed here to provide authentic and timely information. His original articles on all those topics, except opals and gem phenomena, first appeared in National Geographic Magazine. Glamour, intrigue, romance, the quest for treasure those are all vital aspects of humankind s eternal search and love for gemstones. As long as people have roamed the world, they have placed extraordinary value on our gifts from the land and sea. The Wards capture the gem world in captivating, expert detail with an emphasis on the international contemporary scene.

gems, beryl, emerald, Afghanistan, Brazil, Colombia, Zambia, Madagascar, China, Pakistan, Zimbabwe, inclusions

The French chemist N.L. Vauquelin (1763–1829) discovered chromium (Cr) in crocoite (PbCrO₄) from Beresov, Russia, and beryllium (Be) in emerald from Colombia more than 200 years ago. He determined the correct chemical composition of emerald and demonstrated that the difference between beryl and emerald was due to the presence of the coloring agent chromium. Today, emerald is defined by Schwarz and Schmetzer (2002) as “yellowish green, green or bluish green beryl—natural or synthetic—which reveals distinct Cr and/or vanadium (V) absorption bands in the red and blue-violet ranges of its absorption spectra.” Emerald is one of the most valuable gemstones. It is much rarer than diamond and can command a value thousands of times greater than gold. In the colored gemstone market, color is more important than clarity or brilliance in determining the value of an emerald. The green color of emerald arises from the unique geological conditions of its formation in contrasting environments. This article reviews, using state-of-the-art data, the crystal chemistry and formation of emerald, highlighting its paradoxes, as well as the geology of economically significant emerald deposits worldwide, comparing their origins, similarities, and differences.

gems, corundum, history.1, Mughal jewelry, spinel, diamond, beryl, emerald, pearl, ruby, sapphire

gems, beryl, emerald, lore, history, healing gems, anthropology, Colombia, Brazil

Emeralds are like possessing spirits—beautiful but dangerous. Like the espíritos obsessores of Kardecian mysticism, they can overtake the lives of well-meaning devotees and lead them toward perdition. Like Macumba, emeralds may bring comfort and solace, but they can also become a vice and an addiction. Like the exús of Candomblé, they promise wealth to those who know how to handle them, though the profits are fraught with peril. Dealers in emeralds, much like purveyors of spiritual power, are not always to be trusted, and the presence of charlatans and sharp operators only heightens the mystique surrounding the reputedly authentic priestess and the pedra extra, the fine stone hidden in mica schist that promises a life of leisure to its discoverer. This volume seeks to excavate the relations between spirit possession and material possessions. Paul Johnson employs an ethnographic lens on the history of European philosophy to show how “savage” ideas of things possessing men provided a foil for modern notions of men as possessors of things. This chapter examines how perspectives drawn from Afro-Brazilian spirit possession religions can illuminate the largely irreligious emerald trade in the Bahian backlands.