Gems & Gemology最新文献

{"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}

{"title":"Photoluminescence Mapping of Optical Defects in HPHT Synthetic Diamond","authors":"L. Loudin","doi":"10.5741/GEMS.53.2.180","DOIUrl":"https://doi.org/10.5741/GEMS.53.2.180","url":null,"abstract":"oknown as point defects, absorb visible light to produce color (Collins, 1982). In this way, optical centers give rise to the variety of fancy-color diamonds available in the trade. Optical centers can form as a result of impurities in the diamond (such as nitrogen or boron), deformation of the crystal lattice, missing carbon atoms (vacancies), or a combination of these (Collins, 2003; Breeding and Shigley, 2009). Photoluminescence occurs when an optical center is excited to a higher energy state by the absorption of photons and then returns to its ground energy state, emitting light at a specific wavelength or band of wavelengths (Collins, 1992; Eaton-Magaña and Breeding, 2016). There are currently several hundred known optical centers in diamond that produce photoluminescence (e.g., Collins, 1999; Zaitsev, 2001). Photoluminescence (PL) spectroscopy is a powerful tool used in gemological laboratories to verify whether a specimen is natural or synthetic and determine whether its color origin is natural or due to treatment (Eaton-Magaña and Breeding, 2016). One drawback is","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":"46129127","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":"Characterization of Mg and Fe Contents in Nephrite Using Raman Spectroscopy","authors":"Xiaoyan Feng, Yong Zhang, Taijin Lu, Hui Zhang","doi":"10.5741/GEMS.53.2.204","DOIUrl":"https://doi.org/10.5741/GEMS.53.2.204","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":"48672291","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":"Geology and Development of the Lomonsov diamond Deposit, Northwestern Russia","authors":"Karen V. Smith, R. Shor","doi":"10.5741/GEMS.53.2.144","DOIUrl":"https://doi.org/10.5741/GEMS.53.2.144","url":null,"abstract":"","PeriodicalId":12600,"journal":{"name":"Gems & Gemology","volume":"53 1","pages":"144-167"},"PeriodicalIF":2.6,"publicationDate":"2017-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49185487","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":"Carbonado Diamond: A Review of Properties and Origin","authors":"S. Haggerty","doi":"10.5741/GEMS.53.2.168","DOIUrl":"https://doi.org/10.5741/GEMS.53.2.168","url":null,"abstract":"","PeriodicalId":12600,"journal":{"name":"Gems & Gemology","volume":"53 1","pages":"168-179"},"PeriodicalIF":2.6,"publicationDate":"2017-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46343582","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}