Gems & Gemology最新文献

{"title":"Persian Turquoise: The Ancient Treasure of Neyshabur","authors":"Bahareh Shirdam, A. Shen, Ming-xing Yang, Zahra Mokhtari, Hamed Fazliani","doi":"10.5741/gems.57.3.240","DOIUrl":"https://doi.org/10.5741/gems.57.3.240","url":null,"abstract":"GEMS & GEMOLOGY FALL 2021 T is an opaque, blue to green gem material that has been worn, used, and appreciated by different civilizations for thousands of years. Originally called piruzeh in Persian, the gem has spiritual value in Persian culture is such that its name carries the meanings of victory, triumph, and prosperity. In Persian literature, turquoise has been celebrated by poets, and various legends and beliefs are associated with it (Vinogradov et al., 1966). Archeological discoveries from the Deh Luran Plain in western Iran indicate that turquoise was first utilized around 7000 BCE (Hole et al., 1969). The quantity of turquoise artifacts discovered in burial sites suggests the importance of this mineral in this ancient civilization’s traditions. While the estimated age of these artifacts is valid, no scientific study has linked them to any specific deposit. PERSIAN TURQUOISE: THE ANCIENT TREASURE OF NEYSHABUR","PeriodicalId":12600,"journal":{"name":"Gems & Gemology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41965678","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":"Namak Mandi: A Pioneering Gemstone Market in Pakistan","authors":"H. ur Rehman, Bilal, S. Owais, Obaid ur Rahman, Andy H. Shen","doi":"10.5741/gems.57.2.138","DOIUrl":"https://doi.org/10.5741/gems.57.2.138","url":null,"abstract":"","PeriodicalId":12600,"journal":{"name":"Gems & Gemology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46932414","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":"Detection of Color Treatment and Optical Brightening in Chinese Freshwater \"Edison\" Pearls","authors":"Chunhui Zhou, Joyce Wing Yan Ho, Sally Chan Shih, T. Tsai, Ziyin Sun, S. Persaud, L. Qi","doi":"10.5741/gems.57.2.124","DOIUrl":"https://doi.org/10.5741/gems.57.2.124","url":null,"abstract":"","PeriodicalId":12600,"journal":{"name":"Gems & Gemology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45129504","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":"Measurement and Characterization of the Effects of Blue Fluorescence on Diamond Appearance","authors":"Yun Luo, David Nelson, T. Ardon, C. Breeding","doi":"10.5741/gems.57.2.102","DOIUrl":"https://doi.org/10.5741/gems.57.2.102","url":null,"abstract":"","PeriodicalId":12600,"journal":{"name":"Gems & Gemology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48138336","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":"Pearl Classification: The GIA 7 Pearl Value Factors","authors":"Joyce Wing Han Yo, Sally Chan Shigh","doi":"10.5741/gems.57.2.135","DOIUrl":"https://doi.org/10.5741/gems.57.2.135","url":null,"abstract":"GEMS & GEMOLOGY SUMMER 2021 135 Prized by many cultures throughout history and frequently referred to as “The Queen of Gems,” pearls have long been one of the most sought-after gemstones in both the jewelry industry and the world at large. Their unique appearance and the affordability of cultured pearls in the market have allowed their popularity to grow exponentially over the years. Pearls form in a wide variety of sizes, shapes, and colors, and there are numerous different types of pearls, both natural and cultured. This diversity created the need for a way to distinguish their various appearances and qualities. Consequently, a number of different grading systems were developed within the pearl industry over the years. The competing, often company-specific methods and coded terminology made the systems difficult to understand and employ consistently. Agreeing on a universal approach to classify pearls has remained one of the main challenges facing the pearl industry. The idea of devising a pearl classification system similar to GIA’s 4Cs system for diamonds first appeared in Gems & Gemology in 1942 (Rietz, 1942a,b). The author suggested that pearls could be grouped into several categories such as gem quality, extra-fine quality, fine quality, good quality, fair quality, imperfect, and poor quality, based on several factors, namely shape, luster, surface blemishes, color distribution, and iridescence (commonly referred to as orient). This approach was further improved by GIA’s Richard T. Liddicoat Jr., who in 1967 proposed a new system based on the seven pearl value factors (Liddicoat, 1967). Continued refinement eventually resulted in the development of GIA’s current pearl classification system, called the GIA 7 Pearl Value Factors. This comprehensive pearl classification system offers a detailed description of the appearance of loose pearls, strands, and pearls in jewelry. It is a systematic approach to evaluation, through consistent methodology and common terminology that both industry professionals and consumers can understand (Zhou, 2019). This approach and the terminology of GIA’s updated system have already been adopted in many parts of the pearl industry for classifying and describing pearls. The wall chart presented here is based on a poster presentation from the 2018 GIA International Gemological Symposium (Ho and Shih, 2018). It provides the definitions and classification terminology for each of the seven value factors—size, shape, color, luster, surface, nacre, and matching—as well as digital images to illustrate various examples. Pearls fall into one of two varieties: nacreous (resembling mother-of-pearl with lustrous nacre) and non-nacreous (such as conch or melo pearls, lacking lustrous nacre but often displaying flame structure on the surface). This system applies to nacreous pearls (see figure 1) and exclusively for the three dominant types of saltwater cultured pearls: akoya, PEARL CLASSIFICATION: THE GIA 7 PEARL VALUE FACTORS","PeriodicalId":12600,"journal":{"name":"Gems & Gemology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47123094","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":"Internal Structures of Known Pinctada Maxima Pearls: Natural Pearls from Wild Marine Mollucks","authors":"Artitaya Homkrajae, Areeya Manustrong, Nanthaporn Nilpetploy, Nicholas Sturman, Kwanreun Lawangwong, Promlikit Kessrapong","doi":"10.5741/GEMS.57.1.2","DOIUrl":"https://doi.org/10.5741/GEMS.57.1.2","url":null,"abstract":"","PeriodicalId":12600,"journal":{"name":"Gems & Gemology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42632517","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":"Technical Evolution and Identification of Resin-Filled Turquoise","authors":"Ling Liu, Ming-xing Yang, Yan Li, Jingru Di, Rukang Chen, Jia Liu, C. He","doi":"10.5741/GEMS.57.1.22","DOIUrl":"https://doi.org/10.5741/GEMS.57.1.22","url":null,"abstract":"","PeriodicalId":12600,"journal":{"name":"Gems & Gemology","volume":"1 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41756344","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":"How to Calculate Color from Spectra of Uniaxial Gemstones","authors":"Chen Shen, Aaron C. Palke, Ziyin Sun, M. Fairchild","doi":"10.5741/GEMS.57.1.36","DOIUrl":"https://doi.org/10.5741/GEMS.57.1.36","url":null,"abstract":"","PeriodicalId":12600,"journal":{"name":"Gems & Gemology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48205639","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":"Micro-Features of Spinel","authors":"Nathan D. Renfro, John I. Koivula, S. McClure, Kevin Schumacher, J. Shigley","doi":"10.5741/GEMS.57.1.46","DOIUrl":"https://doi.org/10.5741/GEMS.57.1.46","url":null,"abstract":"","PeriodicalId":12600,"journal":{"name":"Gems & Gemology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46803915","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":"Baroque-Era Rose Cuts of Colored Stones: Highlights from the Second Half of the Seventeenth Century","authors":"K. Schmetzer","doi":"10.5741/GEMS.56.4.458","DOIUrl":"https://doi.org/10.5741/GEMS.56.4.458","url":null,"abstract":"GEMS & GEMOLOGY WINTER 2020 Rose cuts encompass a variety of faceting arrangements, all of which lack a flat table (figure 1). In contrast to the considerable literature on the use of rose cuts in diamonds, there has been a dearth of information regarding their use in colored stones. The story of diamond fashioning started with the polishing and/or slight modification of the crystal faces of natural diamond octahedra, creating what is known as the point cut. Thereafter, simple table cuts were developed from the fifteenth century onward, becoming more complex over time (Lenzen, 1966; Falk, 1975; Tillander, 1995; Klein, 2005; Gilbertson, 2007; Ogden, 2018). Diamonds with rose cuts came later as a typical product of the sixteenth and seventeenth centuries, employing a cutting process that began with a rough cleavage fragment from a diamond octahedron. The standard appearance generally consisted of a flat base topped by a dome with six triangular facets at the center. Between the dome top and the base was an intervening layer with six, 12, or 18 additional facets (figure 2). Despite some inconsistency in terminology, these cuts are primarily denoted as Antwerp roses (6 + 6 facets), half-Dutch roses (6 + 12 facets), and full-Dutch roses (6 + 18 facets), respectively (Eppler and Eppler, 1934; Stranner, 1953). Visual evidence of the foregoing historical progression in diamond cuts is readily found in references depicting jewelry objects from bygone eras and in seventeenth-century sketchbooks of goldsmiths or jewelry designers such as T. Cletcher (1629) or G. Légaré (1663) (figure 3; see, e.g., Gans, 1961; Walgrave, 1993a,b; Scarisbrick, 1993). Political and economic circumstances related to the development of rose-cut diamonds are discussed by Kockelbergh et al. (1992) and De Bie (2014). In the decidedly less voluminous literature on colored stones cut without flat tables, the first appearance of such a faceted gemstone in art is found in a sixteenth-century painting by A. Bronzino (1542) portraying Venus, Cupid, Folly, and Time (an allegory of lust) (see Prim, 2018). The oval gemstone in that work shows a crown covered by multiple facets in the form of elongated rhombuses. Other isolated art and jewelry pieces from the second half of the sixteenth century and the seventeenth century likewise offer several examples (see, e.g., Prim, 2019). A notable influx of items displaying colored stones cut without flat tables then occurred with the 1912 discovery of the so-called Cheapside Hoard, dated before the Great Fire of London in 1666. Exemplars are contained in the catalog prepared for the 2014 exhibition BAROQUE-ERA ROSE CUTS OF COLORED STONES: HIGHLIGHTS FROM THE SECOND HALF OF THE SEVENTEENTH CENTURY","PeriodicalId":12600,"journal":{"name":"Gems & Gemology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42183747","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}