Bahareh Shirdam, A. Shen, Ming-xing Yang, Zahra Mokhtari, Hamed Fazliani
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
2021秋季宝石与宝石T是一种不透明的蓝绿色宝石材料，数千年来一直被不同文明佩戴、使用和欣赏。这颗宝石在波斯语中最初被称为piruzeh，在波斯文化中具有精神价值，因此它的名字带有胜利、胜利和繁荣的含义。在波斯文学中，诗人们一直在赞美绿松石，各种传说和信仰都与之有关（Vinogradov et al.，1966）。伊朗西部德卢兰平原的考古发现表明，绿松石最早使用于公元前7000年左右（Hole et al.，1969）。在埋葬地点发现的大量绿松石文物表明了这种矿物在这个古老文明传统中的重要性。虽然这些文物的估计年龄是有效的，但没有科学研究将它们与任何特定的矿床联系起来。波斯绿松石：尼沙布尔的古老宝藏
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H. ur Rehman, Bilal, S. Owais, Obaid ur Rahman, Andy H. Shen
{"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}
Chunhui Zhou, Joyce Wing Yan Ho, Sally Chan Shih, T. Tsai, Ziyin Sun, S. Persaud, L. Qi
{"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}
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
纵观历史，珍珠受到许多文化的珍视，经常被称为“宝石女王”，长期以来一直是珠宝行业和世界上最受欢迎的宝石之一。它们独特的外观和市场上养殖珍珠的可负担性使它们的受欢迎程度多年来呈指数级增长。珍珠的大小、形状和颜色各不相同，有许多不同类型的珍珠，既有天然的，也有养殖的。这种多样性需要一种方法来区分它们不同的外观和品质。因此，多年来，珍珠行业开发了许多不同的分级系统。相互竞争的，通常是公司特定的方法和编码术语使得系统难以理解和一致地使用。就统一的珍珠分类方法达成一致，一直是珍珠行业面临的主要挑战之一。设计一种类似于GIA钻石4c分类系统的珍珠分类系统的想法最早出现在1942年的《宝石与宝石学》(Rietz, 1942a,b)。作者建议根据珍珠的形状、光泽、表面瑕疵、颜色分布和虹彩(通常称为东方)等几个因素，将珍珠分为宝石级、特级、优质、优质、一般、不完美和劣质等几类。GIA的Richard T. Liddicoat Jr.进一步改进了这种方法，他在1967年提出了一个基于七个珍珠价值因素的新系统(Liddicoat, 1967)。持续的改进最终导致了GIA目前珍珠分类系统的发展，称为GIA 7珍珠价值因素。这个全面的珍珠分类系统提供了一个详细的描述外观松散的珍珠，股，珍珠首饰。这是一种系统的评估方法，通过一致的方法和行业专业人士和消费者都能理解的通用术语(Zhou, 2019)。这种方法和GIA更新系统的术语已经被珍珠行业的许多部门采用，用于珍珠分类和描述。这里展示的挂图是基于2018年GIA国际宝石学研讨会的海报展示(Ho and Shih, 2018)。它提供了七个值因素(大小、形状、颜色、光泽、表面、珍珠层和匹配)的定义和分类术语，并提供了数字图像来说明各种示例。珍珠分为两种:珍珠(类似珍珠母贝，有光泽的珍珠层)和非珍珠(如海螺或甜瓜珍珠，缺乏光泽的珍珠层，但表面经常显示火焰结构)。该系统适用于珍珠(见图1)，仅适用于三种主要类型的海水养殖珍珠:akoya珍珠，珍珠分类:GIA 7珍珠价值因素
{"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}
Chen Shen, Aaron C. Palke, Ziyin Sun, M. Fairchild
{"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}
Nathan D. Renfro, John I. Koivula, S. McClure, Kevin Schumacher, J. Shigley
{"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}
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
{"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}
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