Pub Date : 2021-07-01DOI: 10.15964/J.CNKI.027JGG.2021.04.004
Chen Jingjing, Luo Yueping, Wang Yan
Recently, an orange-red tridacna variety appeared in the market.Representative orange-red tridacna samples were selected and a series of systematic gemmological tests and spectral analysis were carried out. The morphological characteristics of the gemstones were observed by microscope, the species composition of samples was tested by infrared spectrometer, and the colour genesis was analyzed by micro-laser Raman spectrometer. The results were compared with those of "golden tridacna" samples which are relatively common in the market. It was found that the infrared spectral peak of orange-red tridacna is consistent with that of tridacna. The characteristic peaks of armanite and pigment related peaks at 1 130 cm-1 and 1 520 cm-1 were measured by Raman spectrometer. Compared with the white part of the orange-red tridacna samples, it was found that the colour genesis is mainly related to natural organic pigment carotene, which belongs to natural colour genesis.
{"title":"Gemmological Characteristic of Orange-Red Tridacna","authors":"Chen Jingjing, Luo Yueping, Wang Yan","doi":"10.15964/J.CNKI.027JGG.2021.04.004","DOIUrl":"https://doi.org/10.15964/J.CNKI.027JGG.2021.04.004","url":null,"abstract":"Recently, an orange-red tridacna variety appeared in the market.Representative orange-red tridacna samples were selected and a series of systematic gemmological tests and spectral analysis were carried out. The morphological characteristics of the gemstones were observed by microscope, the species composition of samples was tested by infrared spectrometer, and the colour genesis was analyzed by micro-laser Raman spectrometer. The results were compared with those of \"golden tridacna\" samples which are relatively common in the market. It was found that the infrared spectral peak of orange-red tridacna is consistent with that of tridacna. The characteristic peaks of armanite and pigment related peaks at 1 130 cm-1 and 1 520 cm-1 were measured by Raman spectrometer. Compared with the white part of the orange-red tridacna samples, it was found that the colour genesis is mainly related to natural organic pigment carotene, which belongs to natural colour genesis.","PeriodicalId":15852,"journal":{"name":"Journal of Gems & Gemmology","volume":"7 1","pages":"29-32"},"PeriodicalIF":0.0,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73041008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-07-01DOI: 10.15964/J.CNKI.027JGG.2021.04.009
W. Shumin, Zhou Qishen, Wang Ge, Zhou Yuqing
In this paper, the factors affecting the hammer price of yellow diamonds were explored and analyzed through the auction data of yellow diamonds from July to September 2019 of Ali Auction. After constructing a five-factor model including auction setting, item description, commodity attribution, buyer competition and bidding strategy, the relevant hypothesis was put forward, and the empirical test was carried out by using correlation analysis and multiple linear regression analysis. It was found that the mark-up range in auction setting, the weight and colour grade of the diamonds in commodity attribute, the bidding times in buyer competition and the jumping bid in bidding strategy all have significant effects on the hammer price. Other factors such as margin, the number of pictures, the status of the end of the auction, and the number of applicants etc. have no significant impact on the hammer price.
{"title":"Influencing Factor Analysis of the Hammer Price of Yellow Diamond Online Auction: A Case Study of Ali Auction Hammer Price","authors":"W. Shumin, Zhou Qishen, Wang Ge, Zhou Yuqing","doi":"10.15964/J.CNKI.027JGG.2021.04.009","DOIUrl":"https://doi.org/10.15964/J.CNKI.027JGG.2021.04.009","url":null,"abstract":"In this paper, the factors affecting the hammer price of yellow diamonds were explored and analyzed through the auction data of yellow diamonds from July to September 2019 of Ali Auction. After constructing a five-factor model including auction setting, item description, commodity attribution, buyer competition and bidding strategy, the relevant hypothesis was put forward, and the empirical test was carried out by using correlation analysis and multiple linear regression analysis. It was found that the mark-up range in auction setting, the weight and colour grade of the diamonds in commodity attribute, the bidding times in buyer competition and the jumping bid in bidding strategy all have significant effects on the hammer price. Other factors such as margin, the number of pictures, the status of the end of the auction, and the number of applicants etc. have no significant impact on the hammer price.","PeriodicalId":15852,"journal":{"name":"Journal of Gems & Gemmology","volume":"138 1","pages":"61-69"},"PeriodicalIF":0.0,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86276139","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-05-01DOI: 10.15964/J.CNKI.027JGG.2021.03.005
Gao Xin, Wang Meijiao, Ye Shuang, Yin Zuo-wei
Purple boulder opal is a relatively new gem variety in the market. At present, the research that related to purple boulder opal is limited to the mineral components and the genesis of its colour. There is no in-depth analysis on the chemical compositions, spectral characteristics and causes of play-of-colour effect. The mineralogical and spectral characteristics of purple boulder opal from Australia are comprehensively studied in this paper. The results showed that the main mineral component of purple boulder opal is amorphous opal, and it contains a small amount of α-cristobalite. The results of EMPA analysis showed that the main component of opal matrix is SiO2, which is more than 96%. The UV-Vis spectrum showed that there are absorption peaks of strong absorption intensity at 407 nm and 480 nm, and totally absorbed above 522 nm. Based on the results of LA-ICP-MS and UV-Vis absorption spectra, the saturation of the purple colour of purple boulder opal is positively correlated with Fe content. SEM results showed that the diameter of SiO2 spheres in the play-of-colour effect area of the purple boulder opal is about 182-240 nm, and the octahedral space around the sphere is about 63-150 nm. Only violet light with wavelength of 400-450 nm can pass through the sphere to form the pure purple opal.
{"title":"Mineralogical and Spectral Characteristics of Purple Boulder Opal from Australia","authors":"Gao Xin, Wang Meijiao, Ye Shuang, Yin Zuo-wei","doi":"10.15964/J.CNKI.027JGG.2021.03.005","DOIUrl":"https://doi.org/10.15964/J.CNKI.027JGG.2021.03.005","url":null,"abstract":"Purple boulder opal is a relatively new gem variety in the market. At present, the research that related to purple boulder opal is limited to the mineral components and the genesis of its colour. There is no in-depth analysis on the chemical compositions, spectral characteristics and causes of play-of-colour effect. The mineralogical and spectral characteristics of purple boulder opal from Australia are comprehensively studied in this paper. The results showed that the main mineral component of purple boulder opal is amorphous opal, and it contains a small amount of α-cristobalite. The results of EMPA analysis showed that the main component of opal matrix is SiO2, which is more than 96%. The UV-Vis spectrum showed that there are absorption peaks of strong absorption intensity at 407 nm and 480 nm, and totally absorbed above 522 nm. Based on the results of LA-ICP-MS and UV-Vis absorption spectra, the saturation of the purple colour of purple boulder opal is positively correlated with Fe content. SEM results showed that the diameter of SiO2 spheres in the play-of-colour effect area of the purple boulder opal is about 182-240 nm, and the octahedral space around the sphere is about 63-150 nm. Only violet light with wavelength of 400-450 nm can pass through the sphere to form the pure purple opal.","PeriodicalId":15852,"journal":{"name":"Journal of Gems & Gemmology","volume":"60 4","pages":"37-43"},"PeriodicalIF":0.0,"publicationDate":"2021-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72463839","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-05-01DOI: 10.15964/J.CNKI.027JGG.2021.03.003
Jin Xiaoting, LI Guogui, Liao Bingbing, Li Xueming, L. Chu
Micaceous quartzose jade is a new kind of jade recently appeared on the market, and its trade name is "strawberry crystal". In view of the problems faced in the tests and researches of the jade, microscopic laser Raman spectrometer, Fourier transform microscopic infrared spectrometer and X-ray energy spectrometer were used to study the characteristics of mineralogy, vibration spectrum and colouring mechanism of the jade. The results showed that the micaceous quartzose jade is mainly composed of crystalline quartz and the secondary (colouring) mineral is manganese-iron bearing muscovite with typical scaly and granular structure. The formation of the purplish red hue of this kind of mica is closely related to the 554 nm absorption peak caused by 6A1→4T1 (4G) transition. The 445 nm absorption peak is caused by the 6A1→4T2 (4G) transition of delectron of the outer layer of the Mn2+, and the 516 nm absorption peak is caused by the spin forbidden transition of Fe2+. The infrared absorption band of manganese-iron bearing muscovite caused by stretching vibration of Al-(Fe, Mn)-OH is located at 3 616 cm-1, and a group of Raman peaks caused by silica backbone vibration are located at 1 071, 746, 697, 628 cm-1 and 408 cm-1, respectively. The Raman peaks caused by lattice vibration and cation exchange are located at 261 cm-1 and 191 cm-1 respectively, which are distinguished from similar mica group minerals.
{"title":"Gemmological and Vibrational Spectrum Characteristics of Micaceous Quartzose Jade \"Strawberry Crystal\"","authors":"Jin Xiaoting, LI Guogui, Liao Bingbing, Li Xueming, L. Chu","doi":"10.15964/J.CNKI.027JGG.2021.03.003","DOIUrl":"https://doi.org/10.15964/J.CNKI.027JGG.2021.03.003","url":null,"abstract":"Micaceous quartzose jade is a new kind of jade recently appeared on the market, and its trade name is \"strawberry crystal\". In view of the problems faced in the tests and researches of the jade, microscopic laser Raman spectrometer, Fourier transform microscopic infrared spectrometer and X-ray energy spectrometer were used to study the characteristics of mineralogy, vibration spectrum and colouring mechanism of the jade. The results showed that the micaceous quartzose jade is mainly composed of crystalline quartz and the secondary (colouring) mineral is manganese-iron bearing muscovite with typical scaly and granular structure. The formation of the purplish red hue of this kind of mica is closely related to the 554 nm absorption peak caused by 6A1→4T1 (4G) transition. The 445 nm absorption peak is caused by the 6A1→4T2 (4G) transition of delectron of the outer layer of the Mn2+, and the 516 nm absorption peak is caused by the spin forbidden transition of Fe2+. The infrared absorption band of manganese-iron bearing muscovite caused by stretching vibration of Al-(Fe, Mn)-OH is located at 3 616 cm-1, and a group of Raman peaks caused by silica backbone vibration are located at 1 071, 746, 697, 628 cm-1 and 408 cm-1, respectively. The Raman peaks caused by lattice vibration and cation exchange are located at 261 cm-1 and 191 cm-1 respectively, which are distinguished from similar mica group minerals.","PeriodicalId":15852,"journal":{"name":"Journal of Gems & Gemmology","volume":"12 1","pages":"19-28"},"PeriodicalIF":0.0,"publicationDate":"2021-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86472618","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-05-01DOI: 10.15964/J.CNKI.027JGG.2021.03.002
Song Qiurong, Shen Andy Hsitien
A batch of unheated and heated rubies from Myanmar were obtained from a gemstone processor in Thailand. The gemmological characteristics, chemical composition characteristics, infrared spectrum characteristics and UV-Vis absorption spectrum characteristics were tested and analyzed, so as to obtain the characteristics of the rubies after heat treatment and distinguish them from the unheated rubies from Myanmar. The test results showed that a large number of secondary melt inclusions were found in the heated rubies, while only mineral crystal inclusions and fluid inclusions were observed in the unheated rubies. In terms of chemical composition characteristics, the average content of Ti element in heated rubies is about 1 000 ppm higher than that in the unheated rubies, and the average content of Fe element in heated rubies is about 100 ppm lower than that in the unheated rubies. Absorption peaks of daspore, structural water and free water can be detected in unheated rubies, but these characteristic absorption peaks can not be detected in heated rubies due to the damage of high temperature. Compared with unheated rubies, the fluorescence peak of heated rubies near 694 nm is stronger and sharper.
{"title":"Comparative Study of Unheated and Heated Rubies from Myanmar","authors":"Song Qiurong, Shen Andy Hsitien","doi":"10.15964/J.CNKI.027JGG.2021.03.002","DOIUrl":"https://doi.org/10.15964/J.CNKI.027JGG.2021.03.002","url":null,"abstract":"A batch of unheated and heated rubies from Myanmar were obtained from a gemstone processor in Thailand. The gemmological characteristics, chemical composition characteristics, infrared spectrum characteristics and UV-Vis absorption spectrum characteristics were tested and analyzed, so as to obtain the characteristics of the rubies after heat treatment and distinguish them from the unheated rubies from Myanmar. The test results showed that a large number of secondary melt inclusions were found in the heated rubies, while only mineral crystal inclusions and fluid inclusions were observed in the unheated rubies. In terms of chemical composition characteristics, the average content of Ti element in heated rubies is about 1 000 ppm higher than that in the unheated rubies, and the average content of Fe element in heated rubies is about 100 ppm lower than that in the unheated rubies. Absorption peaks of daspore, structural water and free water can be detected in unheated rubies, but these characteristic absorption peaks can not be detected in heated rubies due to the damage of high temperature. Compared with unheated rubies, the fluorescence peak of heated rubies near 694 nm is stronger and sharper.","PeriodicalId":15852,"journal":{"name":"Journal of Gems & Gemmology","volume":"65 1","pages":"7-18"},"PeriodicalIF":0.0,"publicationDate":"2021-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85854996","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-05-01DOI: 10.15964/J.CNKI.027JGG.2021.03.001
Zhu Wenfang, D. Ting, Lin Huihuang, Zhu Xiaoxia
Synthetic type Ⅰb yellow diamonds are mainly grown by High Pressure High Temperature(HPHT) process, however, type Ⅰb CVD synthetic yellow diamonds have rarely been reported so far. A yellow type Ⅰb CVD syntheitc diamond sample was recognized for the first time in NGTC Shenzhen Laboratory during daily testing. It is critical for jewelry testing industries to summarize the identification characteristics of this yellow type Ⅰb CVD synthetic diamond, which will be helpful to identify problematic samples efficiently in the future. The means to identify the yellow type Ⅰb CVD synthetic diamond are summarized by collecting the infrared absorption spectrum, ultraviolet-visible absorption spectrum, ultraviolet fluorescence image and photoluminescence spectrum of the sample. The luminescence peaks at 737, 766 nm and 946 nm attributed to [Si-V] defects, and the parallel growth striations observied under fluorescence were diagnostic proofs of CVD synthetic diamonds. No doublet peaks at 596 nm and 597 nm were found and weaker 3 123 cm-1peak was detected, and the obvious 3 107 cm-1 peak, H3 (503.2 nm) emission and N3 (415.2 nm) emission suggested that it has undergone post-growth high temperature annealing to remove the as-grown brown coloration.
{"title":"Identification Characteristic of HPHT-Treated Yellow Type Ib CVD Synthetic Diamond","authors":"Zhu Wenfang, D. Ting, Lin Huihuang, Zhu Xiaoxia","doi":"10.15964/J.CNKI.027JGG.2021.03.001","DOIUrl":"https://doi.org/10.15964/J.CNKI.027JGG.2021.03.001","url":null,"abstract":"Synthetic type Ⅰb yellow diamonds are mainly grown by High Pressure High Temperature(HPHT) process, however, type Ⅰb CVD synthetic yellow diamonds have rarely been reported so far. A yellow type Ⅰb CVD syntheitc diamond sample was recognized for the first time in NGTC Shenzhen Laboratory during daily testing. It is critical for jewelry testing industries to summarize the identification characteristics of this yellow type Ⅰb CVD synthetic diamond, which will be helpful to identify problematic samples efficiently in the future. The means to identify the yellow type Ⅰb CVD synthetic diamond are summarized by collecting the infrared absorption spectrum, ultraviolet-visible absorption spectrum, ultraviolet fluorescence image and photoluminescence spectrum of the sample. The luminescence peaks at 737, 766 nm and 946 nm attributed to [Si-V] defects, and the parallel growth striations observied under fluorescence were diagnostic proofs of CVD synthetic diamonds. No doublet peaks at 596 nm and 597 nm were found and weaker 3 123 cm-1peak was detected, and the obvious 3 107 cm-1 peak, H3 (503.2 nm) emission and N3 (415.2 nm) emission suggested that it has undergone post-growth high temperature annealing to remove the as-grown brown coloration.","PeriodicalId":15852,"journal":{"name":"Journal of Gems & Gemmology","volume":"772 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2021-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85685684","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-05-01DOI: 10.15964/J.CNKI.027JGG.2021.03.006
Guo Jie, Liao Renqing, Zheng Qiuju
Painite belongs to a very rare gem variety, and its gemmological characteristics are rarely reported.In this paper, the painite samples were tested by conventional gemmological intruments, infrared spectrometer, Raman spectrometer, EDS energy spectrometer and photoluminescence spectrum technology in order to provide gemmological data of the variety, and improve the detection efficiency. The results showed that the refractive index of painite is beyond the measurement range of gem refractometer and dichroism is obvious. The typical absorption spectrum can be seen under prism spectroscope. It showed inert under LW ultraviolet lamp, and medium to strong yellow green fluorescence under SW ultraviolet lamp. The density is 3.89±0.02 g/cm3, and its Mohs hardness is 7-8 with shell fracture.The results of IR and Raman spectra showed that the characteristic peaks of the sample were related to the vibration of B-O, Al-O, Ca-O and Zr-O, where [BO3]3- and [BO4]5- coexist. The photoluminescence spectra confirmed the existence of electron hole core in the sample. UV-Vis absorption spectra showed that the absorption peaks of the sample were related to the superposition of Ti, V and Fe. The main elements of the sample measured by EDS spectrometer are consistent with the painite formula.
{"title":"Gemmological Characteristic of Painite","authors":"Guo Jie, Liao Renqing, Zheng Qiuju","doi":"10.15964/J.CNKI.027JGG.2021.03.006","DOIUrl":"https://doi.org/10.15964/J.CNKI.027JGG.2021.03.006","url":null,"abstract":"Painite belongs to a very rare gem variety, and its gemmological characteristics are rarely reported.In this paper, the painite samples were tested by conventional gemmological intruments, infrared spectrometer, Raman spectrometer, EDS energy spectrometer and photoluminescence spectrum technology in order to provide gemmological data of the variety, and improve the detection efficiency. The results showed that the refractive index of painite is beyond the measurement range of gem refractometer and dichroism is obvious. The typical absorption spectrum can be seen under prism spectroscope. It showed inert under LW ultraviolet lamp, and medium to strong yellow green fluorescence under SW ultraviolet lamp. The density is 3.89±0.02 g/cm3, and its Mohs hardness is 7-8 with shell fracture.The results of IR and Raman spectra showed that the characteristic peaks of the sample were related to the vibration of B-O, Al-O, Ca-O and Zr-O, where [BO3]3- and [BO4]5- coexist. The photoluminescence spectra confirmed the existence of electron hole core in the sample. UV-Vis absorption spectra showed that the absorption peaks of the sample were related to the superposition of Ti, V and Fe. The main elements of the sample measured by EDS spectrometer are consistent with the painite formula.","PeriodicalId":15852,"journal":{"name":"Journal of Gems & Gemmology","volume":"8 1","pages":"44-52"},"PeriodicalIF":0.0,"publicationDate":"2021-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83391820","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-05-01DOI: 10.15964/J.CNKI.027JGG.2021.03.004
X. Su, S. Xiaoping
Nanhong agate from Liangshan Yi Autonomous Prefecture of Sichuan Province, China has gained great popularity in the gem market in China for its vibrant colour. Its attractive orange-red colour is generated by fine hematite concentrations. Recently, a new kind of agate named "black seaweed pattern agate", belonging to the family of the Nanhong agates appeared in the local market of Liangshan Prefecture. Microscopic examination showed that the fine red and black grain minerals scattered in various forms such as silkiness and disseminated forms in the sample. Infrared spectrometer, Raman spectrometer and X-ray powder diffraction were used to study the gemmological and mineralogical characteristics of the agate. The results proved that the main mineral component of the agate was quartz with a low relative content of moganite and high degree of order. The crystallinity of the agate is about 6.76. FTIR spectra showed a weak peak at 3 674 cm-1 related to OH-. Combined with the XRD testing result (d=8.418 A), it supported the existence of phyllosilicates in the agate. Raman spectrum of red grain mineal showed peaks at 226, 245, 292 cm-1, which matched well with hematite. Meanwhile the spectrum of black grain was consistent with sulfide minerals (peaks at 342, 377 cm-1). Further testing results of scanning electron microscopy and back scattering diffraction confirmed that most of the black grain mineral is pyrite(FeAs(0.015-0.018 5)S(1.826-1.886)), which belongs to isometric system. According to Raman database, the last peak at 289 cm-1 was identical with chalcopyrite. All these evidence showed pyrite had a paragenetic relationship with chalcopyrite in some area of "black seaweed pattern agate". Another important features were that mineral components and morphological distribution of these black grains were obviously different from features such as Fe and Mn oxides and organic grains that appear in common seaweed pattern agate from other places, which may indicate that the origin of "black seaweed pattern agate" is from Liangshan.
{"title":"Mineralogical Characteristic of Nanhong Agate with Black Seaweed Pattern Mineral Inclusion","authors":"X. Su, S. Xiaoping","doi":"10.15964/J.CNKI.027JGG.2021.03.004","DOIUrl":"https://doi.org/10.15964/J.CNKI.027JGG.2021.03.004","url":null,"abstract":"Nanhong agate from Liangshan Yi Autonomous Prefecture of Sichuan Province, China has gained great popularity in the gem market in China for its vibrant colour. Its attractive orange-red colour is generated by fine hematite concentrations. Recently, a new kind of agate named \"black seaweed pattern agate\", belonging to the family of the Nanhong agates appeared in the local market of Liangshan Prefecture. Microscopic examination showed that the fine red and black grain minerals scattered in various forms such as silkiness and disseminated forms in the sample. Infrared spectrometer, Raman spectrometer and X-ray powder diffraction were used to study the gemmological and mineralogical characteristics of the agate. The results proved that the main mineral component of the agate was quartz with a low relative content of moganite and high degree of order. The crystallinity of the agate is about 6.76. FTIR spectra showed a weak peak at 3 674 cm-1 related to OH-. Combined with the XRD testing result (d=8.418 A), it supported the existence of phyllosilicates in the agate. Raman spectrum of red grain mineal showed peaks at 226, 245, 292 cm-1, which matched well with hematite. Meanwhile the spectrum of black grain was consistent with sulfide minerals (peaks at 342, 377 cm-1). Further testing results of scanning electron microscopy and back scattering diffraction confirmed that most of the black grain mineral is pyrite(FeAs(0.015-0.018 5)S(1.826-1.886)), which belongs to isometric system. According to Raman database, the last peak at 289 cm-1 was identical with chalcopyrite. All these evidence showed pyrite had a paragenetic relationship with chalcopyrite in some area of \"black seaweed pattern agate\". Another important features were that mineral components and morphological distribution of these black grains were obviously different from features such as Fe and Mn oxides and organic grains that appear in common seaweed pattern agate from other places, which may indicate that the origin of \"black seaweed pattern agate\" is from Liangshan.","PeriodicalId":15852,"journal":{"name":"Journal of Gems & Gemmology","volume":"60 1","pages":"29-36"},"PeriodicalIF":0.0,"publicationDate":"2021-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84845657","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-05-01DOI: 10.15964/J.CNKI.027JGG.2021.03.008
Zhou Qishen, Wang Binyan, Liu Hao, Zhao Yue, Zhou Yuqing
Ruby always occupies an important position among coloured gemstones with its bright colour and precious value. Ruby jewelry auctions can be used as an effective means to appreciate investment and avoid market risks. Studying international ruby jewelry auctions can help gem practitioners gain a deeper understanding of the global ruby jewelry auction market, more accurately predict future market trends, and provide investors and collectors ruby jewelry auction information and purchase references. In this paper, the authors collected and sorted the ruby jewelry auction records of 7 auction houses from 2008 to 2019, conducted research on the international ruby jewelry auction market and analyzed the factors that affect ruby jewelry auction prices. The research found that the volume of international ruby jewelry auction market has been increasing continuously in 2008-2015, and has fallen back since then. Sotheby's and Christie's are the most important ruby jewelry auction houses, and China and Switzerland are the most important ruby jewelry auction markets. The price of ruby is affected by multiple factors such as colour, origin, weight, clarity (optimization) treatment, special optical effects, and shapes, which have a significant impact on the price of ruby.
{"title":"Overview of the International RubyJewelry Auction Market and Analysis of Its Price Influencing Factor","authors":"Zhou Qishen, Wang Binyan, Liu Hao, Zhao Yue, Zhou Yuqing","doi":"10.15964/J.CNKI.027JGG.2021.03.008","DOIUrl":"https://doi.org/10.15964/J.CNKI.027JGG.2021.03.008","url":null,"abstract":"Ruby always occupies an important position among coloured gemstones with its bright colour and precious value. Ruby jewelry auctions can be used as an effective means to appreciate investment and avoid market risks. Studying international ruby jewelry auctions can help gem practitioners gain a deeper understanding of the global ruby jewelry auction market, more accurately predict future market trends, and provide investors and collectors ruby jewelry auction information and purchase references. In this paper, the authors collected and sorted the ruby jewelry auction records of 7 auction houses from 2008 to 2019, conducted research on the international ruby jewelry auction market and analyzed the factors that affect ruby jewelry auction prices. The research found that the volume of international ruby jewelry auction market has been increasing continuously in 2008-2015, and has fallen back since then. Sotheby's and Christie's are the most important ruby jewelry auction houses, and China and Switzerland are the most important ruby jewelry auction markets. The price of ruby is affected by multiple factors such as colour, origin, weight, clarity (optimization) treatment, special optical effects, and shapes, which have a significant impact on the price of ruby.","PeriodicalId":15852,"journal":{"name":"Journal of Gems & Gemmology","volume":"16 1","pages":"63-71"},"PeriodicalIF":0.0,"publicationDate":"2021-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83557781","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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