gems, advanced testing, XRF

The recent synthetic technique of gem materials has progressed surprisingly, and newer synthetic gemstones have appeared on the market one after another. Those who are engaged in research and manufacturing synthetic gemstones have placed their great efforts in producing the gemstones which most closely resemble natural stones. Including our country, with research laboratories, universities, and major manufacturing industries, as well as specialized makers such as Gilson and all sorts of fields of the world, research work has been carried out daily. And the synthetic gemstones that have reached the market one after another have caused great confusion in the business of gemstones, and furthermore, made our identification work more difficult. In the identification of gemstones, there is one big restriction. That is “Non-destructiveness.” Therefore, we must conduct our important work of gem identification within the restriction of not causing damage to the gemstones. Up to now, we have employed various testing instruments in measuring the optical characters as well as physical properties to pass judgment as to whether a gemstone is synthetic or natural. However, with the recent synthetic gemstones, it has become increasingly difficult to make the decision with the conventional testing equipment. As means of providing the distinct decision of synthetic or natural origin of all gemstones, we have turned our attention to “Fluorescence X-Ray Analysis” in that place against the situation. From the numerous data obtained up to now, other than the essential components that are included only in synthetic or only in natural stones, and as a result, we have become able to recognize them clearly. In this way, the fluorescence X-ray analysis device has become increasingly important as the indispensable examination technique in our identification work. Presently, in our association, we have installed the fluorescence X-ray analysis device and are utilizing it in the identification work of alexandrite, emerald, corundum, turquoise, black pearl, and so on.

gems, beryl, emerald, gold, Colombia

This is an oversized folder containing 9 leafs of color plates from the exhibit of the same name.

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

gems, novels, emerald, Colombia

In New York Times–bestselling author Gerald A. Browne’s riveting thriller, a down-on-his-luck American makes one last gamble to reap a fortune in the Colombian emerald business After years of stultifying office work, Joseph Wiley will try anything to get rich in a hurry. He’s hustled all kinds of products, but each venture has left him deeper in debt, chained tighter to his office desk. When his latest moneymaker goes up in smoke, Wiley doesn’t even bother to quit his job. He takes every cent he has to the airport and flies south, landing in Colombia, where he will make his millions—or lose his life. In the mountains of Colombia, even an amateur can make a mint digging for emeralds, but an all-powerful syndicate, the Concession, controls the gems. Wiley and his new partner, heiress Lillian Holbrook, play a dangerous, double-crossing game with the Concession and its watchdogs because, for different reasons, they’re both willing to risk everything for the brilliant green stones.

beryl, emerald, Colombia, gems

FORTY FEET below the surface I hovered weightless above the somber skeleton of a ship, a Spanish galleon lost two and a half centuries ago. As I drifted lower, a pinpoint of light caught my eye, a silver droplet gleaming from among the ship’s timbers. Reaching down with one finger, I touched the droplet. It gave under pressure, then suddenly burst into a dozen smaller beads. Mercury. That magical, fluid metal known to the ancients as quicksilver, for its brilliance and its curiously elusive properties. As the tiny beads scattered under my touch, I noticed other droplets of mercury lodged among the remains of small wooden casks stored in rows near the bottom of the ship’s hull (preceding pages). I glanced at my diving partner, Tracy Bowden, and he nodded. Clearly the droplets were no leftover sample of mercury carried aboard ship by some long-ago crewman or passenger. They were the remains of cargo—a major consignment of mercury bound from the Old World to the New for a vital purpose—the recovery of gold and silver. As surely as if each cask bore an imprint of the ship’s name, the droplets identified the sunken vessel: Conde de Tolosa, pride of Spain, tomb of nearly 600 souls. Turning from the wreck, Tracy and I slowly began our ascent. Above us the surface of the sea heaved and rippled in the sun like some vast crucible of molten silver. It was a poignant image, for silver and gold had cost Tolosa her life. The year was 1724, and her grave an obscure West Indian bay. She had sailed from Cádiz, Spain, in July of that year with a companion vessel, Nuestra Señora de Guadalupe. The two ships were bound for Veracruz, Mexico, via Havana on a royal mission: to deliver a consignment of mercury for refining purposes to the Spanish Empire’s extensive gold and silver mines in Mexico.

corundum, quality.10, gems

A practical guide to buying, selling, evaluating, and investing in precious gemstones, written by New York gem dealer Benjamin Zucker. Originally published in 1976 as How to Invest in Gems, this revised second edition reflects the dramatic increases in gemstone prices during the late 1970s and advocates fine rubies, sapphires, emeralds, and diamonds as long-term investments and hedges against inflation and currency depreciation. Individual chapters examine the geological occurrence, mining, cutting, identification, quality factors, geographical origins, and market values of the four principal gemstones, with particular attention to color, clarity, size, and inclusions. Ruby sources discussed include Burma, Sri Lanka, Thailand, Cambodia, Afghanistan, and Kenya; sapphire sources include Kashmir, Burma, Sri Lanka, Thailand, Australia, and Montana; and emerald sources include Colombia, Brazil, Rhodesia, Zambia, Afghanistan, and others. Zucker describes methods of distinguishing natural from synthetic gemstones using microscopy, refractive index measurements, ultraviolet fluorescence, and characteristic inclusions, drawing upon the research of Eduard Gübelin and other gemologists. A substantial section examines the history and operations of De Beers, including its control of diamond production and distribution, relationships with Soviet producers, and methods of stabilizing diamond prices. Other chapters address gem appraisals, auctions, retail and wholesale pricing, and the investment potential of tourmaline, garnet, aquamarine, and other gemstones. Suggested investment portfolios range from $10,000 to $1 million, with recommendations concerning gemstone varieties, sizes, and qualities. Appendices provide comparative gemstone prices from 1968 to 1979, descriptions of major museum collections, an overview of gemological institutions and grading systems, and historical accounts of jewelry craftsmanship, Fabergé, Marco Polo, and Louis XIV. Particularly interesting are the author's firsthand account of purchasing a 94 ct blue star sapphire subsequently exhibited at the American Museum of Natural History and his descriptions of the Iranian Crown Jewels. Illustrated with numerous color and black-and-white photographs of gemstones, inclusions, mining operations, jewelry, and museum treasures, the book offers a revealing contemporary perspective on the international gemstone trade and investment philosophy of the late 1970s, although its price information and some gemological interpretations are now dated.

beryl, emerald, gems

Studies on the refractive indices and specific gravities of natural and synthetic beryls are reviewed. Effects of impurities, temperature and pressure on these propertles are discussed. For synthetic beryls, refractive indices and specific gravity are strongly affected by the water pressure applied during synthesis. The emerald with refractive indices as high as natural emeralds can be synthesized by using the high pressure technique.

synthetic beryl, emerald, gems

corundum, quality.10, gems

Morel reconstructs the French queens’ coronation crown from early inventories and illustrations, arguing that its history was closely intertwined with that of the crown traditionally attributed to Charlemagne. He notes that the queen’s crown weighed about 2.5 kg and was set with numerous pearls and precious stones, including ten rubies, eight sapphires, sixteen balas rubies (spinels), sixteen emeralds, and sixteen sapphires, arranged in settings comparable to those of the king’s crown. The 1534 inventory records a bonnet associated with the crown, while a new crimson-velvet bonnet decorated with pearls, gold, silver, and gemstones was made for the coronation of Louis XIII. Morel traces the crown through successive French coronations and inventories, describing alterations, reuse of gemstones, and the eventual disappearance of the crown during the revolutionary period; the article includes a reconstruction drawing based on the documentary evidence.

gems, corundum, history.1, ancient gems, glyptic,

Although more sapphires have survived from antiquity than rubies and emeralds, they nevertheless remain rare. Among the dozen or so sapphires held in various collections and museums, two stand out, either for their size or for the quality of their engraving. The first, preserved in a private collection in England, depicts a head of Zeus flanked by two letters, Π and Υ, which could be interpreted as the initials of Pyrgoteles, the famous engraver of Alexander the Great (1). Both its engraving and the stone itself, measuring 22.5 mm in height, display exceptional stylistic purity, and it probably belongs to the glyptic art of the fourth century BCE. The second, a heart-shaped sapphire cameo measuring 35 mm in height, belongs to another historical phase: the revival of the classical style and the founding of Augustus’s dynasty.