Gems & Gemology最新文献

{"title":"Gem Virtuosos: The Drehers and Their Extraordinary Carvings","authors":"R. Weldon, C. Jonathan, R. Tozer","doi":"10.5741/gems.53.4.404","DOIUrl":"https://doi.org/10.5741/gems.53.4.404","url":null,"abstract":"the father-and-son team of Gerd and Patrick Dreher are remarkably lifelike. Agate toads appear bumpy, glistening, and slippery. Brimming with personality, their eyes appear to follow the viewer around the room. A carved tiger lily emerges from banded agate (figure 1) as a velvety, dappled flower, its petals enticingly curling inward. And on the backs of these petals, details of the flower’s physiognomy are scrupulously maintained. Much like the gem materials from which they are carved, these works are one-of-a-kind creations. Decades of experience between the two imparts virtuosity to their work, as well as a sense of humor often depicted in the subjects. Today, Gerd is globally acknowledged as a master of the craft, while Patrick has emerged from the younger generation, adding new carving techniques to the family repertoire. This enhances the formidable range of skills that have been passed down through the Dreher family for 13 generations. Following in the path of their ancestors, the Drehers’ ability to render the anatomy of flora and fauna in astonishing detail demands an intimate knowledge of their subject matter, not to mention a deep understanding of the characteristics and attributes of the gem materials they carve. The Drehers study rough gem material, sometimes for years. From these observations they conceive a three-dimensional outcome and then set to work bringing the stone to life (figure 2). A growing collection of diamond-sintered tools, and a thorough understanding of how to use them, underpins their closely guarded lapidary techniques.","PeriodicalId":12600,"journal":{"name":"Gems & Gemology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2018-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44132503","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Saltwater Pearls from the Pre- to Early Columbian Era: A Gemological and Radiocarbon Dating Study","authors":"Chunhui Zhou, G. Hodgins, T. Lange, K. Saruwatari, Nicholas Sturman, L. Kiefert, K. Schollenbruch","doi":"10.5741/GEMS.53.3.286","DOIUrl":"https://doi.org/10.5741/GEMS.53.3.286","url":null,"abstract":"ing is permitted with credit to the source. Libraries are permitted to photocopy beyond the limits of U.S. copyright law for private use of patrons. Instructors are permitted to reproduce isolated articles and photographs/images owned by G&G for noncommercial classroom use without fee. Use of photographs/images under copyright by external parties is prohibited without the express permission of the photographer or owner of the image, as listed in the credits. For other copying, reprint, or republication permission, please contact the Managing Editor. Gems & Gemology is published quarterly by the Gemological Institute of America, a nonprofit educational organization for the gem and jewelry industry. Postmaster: Return undeliverable copies of Gems & Gemology to GIA, The Robert Mouawad Campus, 5345 Armada Drive, Carlsbad, CA 92008. Our Canadian goods and service registration number","PeriodicalId":12600,"journal":{"name":"Gems & Gemology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2017-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47393837","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Colombian Emerald Industry: Winds of Change","authors":"Darwin Fortaleche, Andrew Lucas, J. Muyal, Tao Hsu, P. Padua","doi":"10.5741/GEMS.53.3.332","DOIUrl":"https://doi.org/10.5741/GEMS.53.3.332","url":null,"abstract":"C is synonymous with fine emerald, and production is believed to date back well over a thousand years. Over the centuries the beautiful verdant gemstone, which emerges from areas that are also a lush green, has been linked to violence and human exploitation. Nevertheless, the desire of the Colombian people to mine for this treasure and strike it rich has endured, with enough dreams coming true to drive their passion. In recent years, industry changes have accelerated, perhaps more profoundly than ever before. While gov-","PeriodicalId":12600,"journal":{"name":"Gems & Gemology","volume":"53 1","pages":"332-358"},"PeriodicalIF":2.6,"publicationDate":"2017-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45382368","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Photoluminescence Spectra of Emeralds from Colombia, Afghanistan, and Zambia","authors":"D. Thompson, C. Bayens, M. Morgan, Taylor J. Myrick, N. E. Sims","doi":"10.5741/GEMS.53.3.296","DOIUrl":"https://doi.org/10.5741/GEMS.53.3.296","url":null,"abstract":"","PeriodicalId":12600,"journal":{"name":"Gems & Gemology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2017-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43482470","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Observations on HPHT-Grown Synthetic Diamonds: A Review","authors":"S. eaton-magaña, J. Shigley, C. Breeding","doi":"10.5741/GEMS.53.3.262","DOIUrl":"https://doi.org/10.5741/GEMS.53.3.262","url":null,"abstract":"sure, high-temperature (HPHT) process have been commercially available since the mid1990s. This article presents statistical information and distinctive identification features based on a review of data gathered by GIA, principally at the New York and Carlsbad laboratories, for several thousand HPHT-grown synthetic diamonds. This study includes all HPHT synthetic diamonds submitted to GIA between 2007 (the year GIA started issuing Synthetic Diamond Grading Reports) and 2016. No summary has been published on such a large number of HPHT synthetic samples. We describe here the diagnostic means of identification, with an emphasis on the goods currently being sold for jewelry use. Box A details some of the most important identification criteria that may be used by gemologists. Of this sample set, 12% were colorless to nearcolorless (D–J), 12% blue, 13% yellow, 4% pink to red, and 54% yellowish orange to orangy yellow (e.g., figure 1). The remaining 5% showed other colors, including green-yellow and brown-orange. This set represents both as-grown and treated colors. While some samples were purchased by GIA on the market or from manufacturers, or were loaned or donated to us by manufacturers for study purposes, most were sub-","PeriodicalId":12600,"journal":{"name":"Gems & Gemology","volume":"52 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2017-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48811187","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"True Colors of \"Dalmatian Jasper\"","authors":"T. Powolny, M. Dumańska‐Słowik","doi":"10.5741/GEMS.53.3.325","DOIUrl":"https://doi.org/10.5741/GEMS.53.3.325","url":null,"abstract":"","PeriodicalId":12600,"journal":{"name":"Gems & Gemology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2017-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45827669","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Synthetic Star Sapphires and Rubies Produced by Wiede's Carbidwerk, Freyung, Germany","authors":"K. Schmetzer, H. Gilg, H. Bernhardt","doi":"10.5741/GEMS.53.3.312","DOIUrl":"https://doi.org/10.5741/GEMS.53.3.312","url":null,"abstract":"","PeriodicalId":12600,"journal":{"name":"Gems & Gemology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2017-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46339004","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An Update on Tourmaline from Luc Yen, Vietnam","authors":"N. T. Nhung, L. T. Hương, N.T.M. Thuyet, T. Häger, Nguyen Thi Le Quyen, Tran Thi Thu Duyen","doi":"10.5741/GEMS.53.2.190","DOIUrl":"https://doi.org/10.5741/GEMS.53.2.190","url":null,"abstract":"","PeriodicalId":12600,"journal":{"name":"Gems & Gemology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2017-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44575696","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Big Sky Country Sapphire: Visiting Montana's Alluvial Deposits","authors":"Tao Hsu, Andrew Lucas, R. Kane, S. McClure, Nathan D. Renfro","doi":"10.5741/GEMS.53.2.215","DOIUrl":"https://doi.org/10.5741/GEMS.53.2.215","url":null,"abstract":"S has been mined in the western U.S. state of Montana for more than a century and a half. Historically, gem-quality sapphires have been mined commercially in four main areas in southwestern Montana, shown in figure 1: the upper Missouri River gravel bars (1865), Dry Cottonwood Creek (1889), Rock Creek (1892), and Yogo Gulch (1895). Today, the first two areas remain quite active, while operations in Yogo Gulch and Dry Cottonwood Creek have been suspended for many years. To better understand the characteristics of Montana sapphire and record current mining and commercial activities, GIA sent a team to visit the placer deposits at the upper Missouri River and Rock Creek areas in August 2015. Since the latter half of the 19th century, Montana’s history has been intertwined with gold, silver, and copper mining. Corundum was discovered during the course of gold mining activities in southwestern Montana. Before the 1940s, the state’s alluvial sapphire deposits were exploited mainly to supply the watch industry, but production fell dramatically with the use of synthetic sapphire in watch bearings (Emmett and Douthit, 1993). Among Montana’s secondary deposits, Rock Creek (figure 2) is the only area mined specifically for sapphire from its discovery in 1892 until World War II (Clabaugh, 1952). While Yogo Gulch is a primary deposit, the placer deposits at Rock Creek, Dry Cottonwood Creek, and the upper Missouri River near Helena have been a matter of speculation among researchers trying to work out the origin of these sapphire crystals. Research indicates that they were carried to the surface by volcanic activity, but their ultimate origin is still an open question, even after about 125 years of searching (e.g., Pratt, 1906; Clabaugh, 1952; Garland, 2002; Berg and Dahy, 2002; Berg, 2014; Zwaan et al., 2015). Due to the lack of significant sapphire-bearing host rock outcrops in these areas, the search and discussion continue. The glamour of the sapphires, the mysteries of their origin, the area’s mining history, and the natural beauty of Big Sky country are an intriguing combination (figure 3).","PeriodicalId":12600,"journal":{"name":"Gems & Gemology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2017-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49545178","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Inclusions in Natural, Synthetic, and Treated Sapphire","authors":"Nathan D. Renfro, John I. Koivula, J. Muyal, S. McClure, Kevin Schumacher, J. Shigley","doi":"10.5741/GEMS.53.2.213","DOIUrl":"https://doi.org/10.5741/GEMS.53.2.213","url":null,"abstract":"Figure 1. Sapphires from a variety of sources. Faceted stones (left to right): 6.36 ct pink/orange (padparadscha), 1.63 ct pink, 4.76 ct violet, 5.43 ct violet purple, 3.03 ct blue, 2.12 ct blue, 8.06 ct yellow, 3.46 ct yellow, 2.00 ct orange, and 1.01 ct deep orange. Crystals (left to right): 9.88 ct pink, 17.80 ct violet, 30.07 ct purple, 42.13 ct blue, 10.84 ct yellow, and 5.86 ct yellow-orange. From the GIA Eduard J. Gübelin Collection and Bill Larson, Pala International. Photo by Robert Weldon/GIA.","PeriodicalId":12600,"journal":{"name":"Gems & Gemology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2017-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46972218","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}