Gems & Gemology最新文献

{"title":"Blue Sapphires from Mogok, Myanmar: A Gemological Review","authors":"Wasura Soonthorntantikul, Ungkhana Atikarnsakul, W. Vertriest","doi":"10.5741/gems.57.4.292","DOIUrl":"https://doi.org/10.5741/gems.57.4.292","url":null,"abstract":"","PeriodicalId":12600,"journal":{"name":"Gems & Gemology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2022-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48130660","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":"Purple Gem Spinel from Vietnam and Afghanistan: Comparison of Trace Element Chemistry, Cause of Color, and Inclusions","authors":"P. Belley, Aaron C. Palke","doi":"10.5741/gems.57.3.228","DOIUrl":"https://doi.org/10.5741/gems.57.3.228","url":null,"abstract":"GEMS & GEMOLOGY FALL 2021 Gem-quality spinel occurs in a variety of colors as a result of a diverse array of possible chromophores and chromophore combinations (Schmetzer et al., 1989; Andreozzi et al., 2019): combinations of Fe2+ and Fe3+ (light blue/violet to green to black with increasing Fe concentration; Hålenius et al., 2002); Co2+ (blue; Shigley and Stockton, 1984; D’Ippolito et al., 2015); Cr3+ (red); and V3+ (orange; Andreozzi et al., 2019). Vivid spinels colored by cobalt (blue) and chromium (red) are particularly sought after in the gem trade. Purple spinel (figure 1) is generally colored by Fe or by a combination of Cr, V, and subordinate Fe (Andreozzi et al., 2019). The current study compares the chemical composition and color of two purple spinel samples, from Vietnam and Afghanistan (figure 2), to each other and in the PURPLE GEM SPINEL FROM VIETNAM AND AFGHANISTAN: COMPARISON OF TRACE ELEMENT CHEMISTRY, CAUSE OF COLOR, AND INCLUSIONS","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":"42549106","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: Cultured Pearls from Operated Marine Mollusks","authors":"Artitaya Homkrajae, Nanthaporn Nilpetploy, Areeya Manustrong, Nicholas Sturman, Kwanreun Lawanwong, Promlikit Kessrapong","doi":"10.5741/gems.57.3.186","DOIUrl":"https://doi.org/10.5741/gems.57.3.186","url":null,"abstract":"GEMS & GEMOLOGY FALL 2021 P inctada maxima (the silveror gold-lipped pearl oyster), Pinctada margaritifera (the blacklipped pearl oyster), and Pinctada fucata (martensii) (“the akoya pearl oyster”) are the main mollusks of the Pinctada genus that are commercially farmed. They are routinely used to produce bead cultured (BC) pearls and, as a consequence, sometimes also produce non-bead cultured (NBC) pearls (Otter et al., 2014; Sturman et al., 2016; Nilpetploy et al., 2018a). P. maxima is the largest species in the genus (Scarratt et al., 2012) and generally requires a minimum two-year growth period to yield BC pearls with the thickest nacre layers of all BC pearls (Gervis and Sims, 1992; Cartier and Krzemnicki, 2016). Cultured pearls from the P. maxima mollusk are often referred to as “South Sea” in the market. Australia is the largest producer of white P. maxima (silver-lipped) cultured pearls, while Indonesia, Myanmar, and the Philippines are major producers of “golden” P. maxima (gold-lipped) cultured pearls. The farms producing these pearls are located between the Tropic of Cancer and the Tropic of Capricorn, which coincides with the native P. maxima mollusk’s geographic distribution. The silver-lipped shells are found mostly south of the equator, while the gold-lipped shells populate the region north of the equator (Strack, 2006). P. maxima mollusks used for pearl culturing production in Australia are predominantly wildcaught shells collected in accordance with the annual quota that takes the shell sizes into account (between 120 and 175 mm shell length) and allows fishing INTERNAL STRUCTURES OF KNOWN PINCTADA MAXIMA PEARLS: CULTURED PEARLS FROM OPERATED MARINE MOLLUSKS","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":"46992709","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":"First Identification of Sudoite in Caribbean Ceramic-Age Lapidary Craftsmanship","authors":"Alain Queffelec, L. Bellot‐Gurlet, E. Foy, Y. Lefrais, E. Fritsch","doi":"10.5741/gems.57.3.206","DOIUrl":"https://doi.org/10.5741/gems.57.3.206","url":null,"abstract":"","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":"46064450","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":"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}