The gems and jewelry market in China is entering the stage of stock economy, and its supply chain and industrial chain have been rapidly adjusted, transformed and upgraded. The demands for paperless, digital, and intelligent gem certificates have also been increasing a lot. In the past few years, in order to promote the high-quality development of the domestic gems and jewelry industry, the research team and the digital construction team of National Gems ＆ Jewelry Testing Co. Ltd（NGTC） have used digital storage, digital characterization, big data computing, artificial intelligence detection, as well as modern anti-counterfeiting tracing codes and chains to actively promote the digital and intelligent testing of gems and jewelry. We are launching the digitally upgraded service of “one item, one certificate, one code, and one chain”, which provides technical supports for digital upgrades of the supply chain and industrial chain as well as the possible opening for the recycling market for the used gem and jewelry products.

采用红外吸收光谱、拉曼光谱、紫外-可见-近红外吸收光谱等无损分析技术,并结合激光诱导击穿光谱和电子探针对澳大利亚孟席斯祖母绿的光谱特征、成分特征和颜色成因进行了研究.红外光谱分析显示孟席斯祖母绿具有[Si6O18]基团振动特征,其结构孔道中的Ⅱ型水吸收强于Ⅰ型水;拉曼光谱特征峰主要在323 cm-1、397 cm-1、685 cm-1和1067 cm-1,并可检测到142 cm-1和190 cm-1等弱散射峰;紫外-可见-近红外吸收光谱主要由Cr3+、V3+、Fe2+和Fe3+的吸收组成,其中424 nm和611 nm的吸收由Cr3+和V3+联合作用导致,644 nm、661 nm和682 nm的吸收由Cr3+产生.结合Cr2O3含量显著高于V2O3的化学成分特征,表明孟席斯祖母绿主要由Cr致色.同时将孟席斯祖母绿与云南祖母绿进行对比分析,为孟席斯祖母绿的宝石学鉴定和质量评价提供依据.

China is the world's largest producer of industrial and gem-quality synthetic diamonds, particularly HPHT-grown products. In 2018, production of HPHT synthetic diamonds rose to 18 billion carats of industrial rough and more than 5 million carats of gem-quality rough material. This article summarises the production technology, product quality and output from various companies producing gem-quality HPHT- and CVD-grown synthetic diamonds in China. In recent years, 'hybrid diamonds' (comprised of natural diamond with a CVD overgrowth) have raised identification concerns, and we review differences in the fluorescence, structure and infrared spectrum of the CVD and natural layers. In addition, we briefly discuss diamond-detection devices developed and used in NGTC's laboratories, such as the GV5000. Finally, we compare the gemmological properties of colourless to near-colourless natural and synthetic diamonds.

Large grained synthetic diamond single crystals have been synthesized by international advanced six-sided top hydraulic press by Ji'nan Zhongwu New Material Co. Ltd. To characterize the quality of these synthetic diamonds and establish the identification principles, 225 large colorless, yellow, and blue HPHT synthetic diamonds produced by the company were studied by stereoscopic microscope, multi-spectral induced luminescence imaging system (GV5000), infrared absorption spectrometer (FT- IR), diamond photoluminescence spectrometer (PL5000), laser induced breakdown spectrometer (LIBS) and X-ray energy dispersive spectrometer (EDS) and compared to natural diamonds. The crystal morphology of HPHT synthetic diamonds is mainly composed of octahedral (111) plane and cubic (100) plane. The yield rate of the round bright cut diamonds is between 20% and 67 0. The clarity grades of colorless HPHT synthetic diamonds range from VVS to P, and color grades are between D to H. GV5000 is employed to perform a study of both growth structure and luminescence characteristics of the samples. The cubic-octahedral luminescence patterns related to crystal growth structure can be observed in all samples of three colors. The colorless samples show strong blue fluorescence and phosphorescence. The luminescence peak is at 495 nm, which is related to the paramagnetic nitrogen in the lattice. The blue samples show blue to greenish blue fluorescence and blue phosphorescence, with the luminescence peak at 501 nm, related to the paramagnetic nitrogen and boron in the lattice. The yellow samples show weak green fluorescence and phosphorescence and the luminescence peaks related to Ni} are at 556 and 883 nm. Synthetic diamonds with those features above can be distinguished from natural ones. Infrared absorption spectra show that the colorless HPHT synthetic diamonds having no significant nitrogen-related absorption at 1 332 similar to 1 100 cm(-1), with boron (B-0) related absorption at 2 802 cm(-1), are classified as type II a containing a small amount of boron. The blue HPHT synthetic diamonds are type H b with strong boron-related absorption at 1 294 cm(-1). The yellow HPHT synthetic diamond samples are type I b with obvious absorption peaks at 1 130 and 1 344 crn-' which are caused by single nitrogen. Luminescence peaks related to Ni defects at 659, 694, 708, 714 and 883 nrn are observed in colorless, blue and yellow samples under photoluminescence spectra (PL5000). In contrast, natural colorless and yellow diamonds are usually type I a, with infrared absorption peaks at 1 282 and 1 175 crn-' caused by aggregate nitrogen. Zero phonon lines at 415 nm (N-3) can be detected by photoluminescence spectra. Spectral features caused by isolated nitrogen, boron and nickel are extremely rare in natural colorless and yellow diamonds. Therefore, infrared absorption spectra and photoluminescence spectra features can be used as the significant evidence for identification. The main composition of the extrusive inclusions in colorless HPHT synthetic diamonds turns out to be Fe by LIES. EDS analysis displays that among samples with a relatively large number of inclusions, Fe is detected in blue and colorless samples, and Fe and Ni are tested in yellow samples. Both Fe and Ni are compositions of inclusions, which can be used as one of the identifiable characteristics of HPHT synthetic diamonds. In conclusion, the large grained HPHT synthetic diamonds can be distinguished from natural diamonds based on the fluorescence and phosphorescence characteristics under ultra-short ultraviolet light irradiation (GV5000), accompanied by infrared absorption spectra, photoluminescence spectra (PL5000) and X-ray energy dispersive analysis features.

由于目前国内白色K金样品成分复杂、配方更新较快、缺乏可用于生产控制和检测工作使用的白色金合金标准样品,特别是含钯配方的标准样品.采用特殊的熔炼铸造工艺研制了主要成分为金、银、铜、锌、镍、钯、铟和铁等8种元素,金的质量分数范围为80％～37.5％的白色金合金标准样品.利用能量色散型X射线荧光光谱仪(XRF)、波长色散型XRF、电感藕合等离子体发射光谱仪(ICP-AES)和电位滴定仪等仪器设备对标准样品进行均匀性检验、稳定性测试、化学定值等,结果表明标准样品的均匀性和稳定性良好,定值准确,工作曲线线性良好.因此,该标准样品作为国家标准样品,可应用于白色金合金饰品的分析方法的确认及检测过程中的质量控制.

采用电感耦合等离子体发射光谱仪(ICP-AES)测定铂含量的强度比值法(GB/T 21198.2-2007)是比较常用的方法,经过对该法的测试条件、标准溶液、强度积分面积优化后,对钯含量为80％、40％和20％的铂钯二元配方样品进行检测,探讨优化后的方法对钯含量较高的样品检测准确性.结果表明,优化后的方法,对于钯含量较高的铂钯合金,检测结果的稳定性和准确性较好,适用于高钯含量的铂钯配方首饰样品.

The nephrite with dendrite pattern from Dahua, Guangxi Province, is a special kind of nephrite jade.The nephrite with variety of dendrite pattern ("Shuicaohua") is an unique species of nephrite from Dahua, Guangxi Province.In this paper, the nephrite with variety of dendrite pattern was studied with gemmological tests, polarizing microscope, electron microprobe (EPMA), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy and X-ray diffraction(XRD).The gemmological testing results showed that the refractive index of samples is between 1.59 and 1.61 by point measurement and its average is 1.60.The density is between 2.89 and 2.94 and its average is 2.91.The surface of samples have variety of dendrite pattern("Shuicaohua").By observing the mineral slices under polarizing microscope, the mineral component of the samples is tremolite.The textures of tremolite are classified in two types.One is fibrous intergrowth crystalloblastic texture, and the tremolite grains are distributed uniformaly and its content is more than 95% in general.The other is flaky intergrowth crystalloblastic texture, and the tremolite grains is distinctly larger and its content is less than 5%.According to the electron microprobe (EPMA) test, the content of MnO in white-gray tremolite (without dendrite pattern) is between 0.21% and 0.35%, and the content of MnO of dendrite pattern is between 0.94% and 3.96%.It is concluded that the dendrite pattern ("Shuicaohua") is caused by MnO.The formation of dendrite pattern ("Shuicaohua") should be probably due to fracture filled with MnO.

In recent years, distinguish of amber and copal resin and origin identification of amber are hot topics in academic research.Identification is always with the help of Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy and other means.Although there are some differences in IR and Raman spectra, there are still some similarities.The results do not completely distinguish amber and the copal resins.In the paper, the organic compounds in amber and copal resin were tested by Gas Chromatography-Mass Spectrometer (GC-MS), based on the literatures of both home and abroad.GC-MS showed that the diterpenoids of amber and copal resin are similar, but because of the low maturity of copal resin and the high content of diterpene monomer, there are some components of the difference.Amber non-polar organic compounds are mostly pimaric acid, isopimaric acid and abietic acid.The combination of TIC spectrum and Fourier transform infrared spectroscopy can be used as the basis for the determination of amber and copal resin.

Natural diamonds commonly contain polymeric nitrogen and have complex growing textures, whereas synthetic diamonds do not contain nitrogen or do contain single nitrogen and have typical growing textures related to the synthetic process. Using these characteristics, natural and synthetic diamonds can be distinguished. However, effective identification on melee-sized diamonds or mounted jewelry is not feasible by conventional instruments. A multi-spectral induced luminescence imaging system, GV5000 has been invented, and is described in this paper. Through improving the excitation light source, the light filter, the device configuration, and testing methods, the fluorescence and phosphorescence features of multiple melee-sized diamonds (≥0.002 ct) can be observed simultaneously. An efficient and precise method to identify colorless melee-sized natural and synthetic diamonds on the basis of the luminescent characteristics has also been established. 9015 samples were analyzed by GV5000 and screening results were checked by infrared spectroscopy, and photoluminescence spectroscopy, 97% of the natural diamonds display blue fluorescence without phosphorescence. Moreover, the luminescence of synthetic diamonds is different from that of natural ones. This new method erases the influences of size and shape of samples and increases the accuracy and efficiency of the identification on melee-sized diamonds. The screening rates of natural and synthetic diamonds are as high as 97% and 100%, respectively.

The identification of CVD synthetic diamonds has become a challenge for the gem industry. Recently, a faceted 0.61 ct CVD synthetic diamond (VVS2 clarity and L colour) was submitted to NGTC's Shenzhen Laboratory without disclosure. A bluish green fluorescence pattern similar to the 'tree ring' growth features seen in natural diamonds was observed in the table of the sample with the DiamondView. X-ray topography and Laue diffraction revealed that the crystallographic orientation of the table facet was inclined approximately 20 degrees to the {111} octahedral plane, rather than being oriented in the typical {100} cubic direction. The appearance of this growth pattern could cause confusion, and vigilance is needed to assess the observed pattern in combination with the luminescence colour in differentiating between CVD synthetic and natural diamond. The X-ray topograph and Si-related photoluminescence (PL) doublet at 737.6/737.9 nm clearly indicate a CVD synthetic origin for this sample. The presence of PL peaks at 415 nm (N3) and 503.2 nm (H3), as well as mid-IR absorption at 3107 cm(-1), indicate that the sample underwent post-growth high-temperature, high-pressure (HPHT) treatment. (C) 2015 The Gemmological Association of Great Britain

为查明市场上的一类相对密度在2.88～3.30的浅色硬玉岩相对密度变化的原因,进而为该类玉石的鉴定、命名提供理论基础,笔者利用显微放大观察、电子探针、X射线粉末衍射和X射线荧光光谱分析方法,对该类不同相对密度浅色硬玉岩样品的化学成分、矿物组成和显微结构进行了综合对比研究.研究表明,该类浅色硬玉岩样品主要矿物组成为硬玉,次要矿物为钠长石、方沸石、钠云母;硬玉与次要矿物的含量变化是造成其相对密度值变化的主要原因,随着钠长石、方沸石等的含量增加,样品的相对密度降低;显微结构对样品相对密度值变化有间接的影响,样品中硬玉粒度越悬殊,交代充填结构越显著,其相对密度越低.因此,笔者建议在对含共生矿物的翡翠进行定名时应考虑其中硬玉含量,并利用相对密度、表面特征等进行验证.

The key parameter to determine whether jadeitite can be named gem grade jadeitite 'jadeite jade' or not is the content (the mass fraction) of jadeite in jadeitite. So far, most methods to determine the mass fraction of mineral in rock are destructive, which is not suitable in gem detection. Based on the changes of mineral composition and mass fraction of mineral in jadeitite, a non-destructive method by measuring the relative density of jadeitite was established in order to get the mass fraction of jadeite. By Static Water Density Method, 186 pieces of jadeitite samples with relative densities of 3.30-3.24 were divided into groups according to different densities. The main mineral composition and mass fraction of minerals in jadeitite were analyzed by X-ray Powder Diffraction, Manual Heavy-sand Analysis, Electron Probe Microanalysis, Infrared Spectrometry and Raman Spectrometry. The linear relationship between the mass fraction of jadeite and the relative density of jadeitite was statisticstically analyzed. Results show that the main minerals in jadeitite are jadeite, albite, and analcite. As the mass fraction (wA) of jadeite decreases, those of albite and analcime increase, and the measured specific gravities (SG) of jadeitite change accordingly. The relationship between them is wA=1.3454 SG-3.4531 (r=0.9814), showing a good linear dependence relation. Because the measured specific gravity of jadeitite is approximately equal to the theoretical one, mass fraction of jadeite is obtained by measuring the specific gravity of jadeitite. This non-destructive method applies to jadeitite with a specific gravity of 3.3-3.0, jadeite content of 95%-60%, and sum mass fractions of jadeite and albite of 90%-97%.

2015年,国家珠宝玉石质量监督检验中心(NGTC)深圳实验室先后在送检的镶嵌饰品中检测出多批次混杂在配镶副石中的无色小颗粒高压高温(HPHT)合成钻石,本文对这些饰品的特征进行了详细的测试和分析.结果表明,小颗粒高压高温合成钻石样品中可见Fe、Ni等金属包裹体,并大多具有磁性;红外光谱可检测到弱的2 802 cm-1跟B相关的吸收峰;钻石观察仪下可见蓝色-蓝绿色荧光的几何状生长分区以及强蓝色磷光;紫外-可见-近红外光谱可检测到与Ni相关吸收线(685,880 nm);小颗粒钻石自动排查仪(AMS)测试结果均为"referⅡ型"或"refer".虽然前人对无色高压高温合成钻石已有少量研究,但在实验室送检样品的配石中属首次发现,这应引起重视和警惕.

It is widely considered that albite jade is mainly composed of albite,actinolite,chlorite,epidote,quartz,jadeite,etc.However,in-depth analysis of mineral components in albite jade is lacking,and relative knowledge is incomprehensive.The gemmological characteristics,mineral components,texture feature and degree of order of albite jade are studied in this paper.Refering to division of varieties in jadeite,the albite jade according to its basement and colour,can be classified into five kinds:(1)Icy-like albite jade;(2)Icy-like albite jade with"blue flower";(3)Green albite jade with white basement;(4)Cottonrose-like albite jade;(5)Dark-green albite jade.The mineral components of albite jade are studied by using many kinds of analytical methods,such as conventional gemmological methods,polarizing microscope,electron microprobe and X-ray powder diffraction.The results show that the refractive index of the albite jade is about 1.51-1.53(point measurement)and amphibole part is about 1.63(point measurement).The common colour of albite jade is colourless,white,green,grayish-green,yellow,brown,etc.None of the varieties have obvious ultraviolet fluorescence.The crystal morphologies of mineral under polarizing microscope are mainly hypidiomorphic or allotriomorphic granular,short prismatic and fibrous,and the textures are mainly the mylonitic and fibrous granular crystalloblastic textures.Albite contained in albite jade often shows following structure types:tabular,foliaceous,isometric granular and sugar granular.Polysynthetic twin is common and twin lamellae is clear.The white veins or tinea spots in it are often composed of jadeite.The jadeite in colourless and transparent albite jade presents white grains or masses and takes the shape of white foams,which is also white and granulous and short prismatic under polarizing microscope.Amphibole is found in the icy-like albite jade with"blue flower",dark-green and green albite jade with white basement("Maw-sit-sit"jade),which is of dark-green phenocryst and light green fibrous and long column.The slices of the samples are observed and 50probe-testing points are circled,the ionic numbers are analyzed and calculated.For the calculation of crystalchemical formulate,cationic method is used.Electronic valence balance(Fe3+,Fe2+)is applied to categorize pyroxene and amphibole.The main mineral component of Albite jade is albite and the accessory minerals are richterite,magnesiokatophorite,edenite,jadeite,omphacite and kosmochlor,with minor accessory strontium carbonate,chromite and hematite.This paper doubts that the minerals of"blue flower"in albite jade are chlorite and epidote.The authors confirm the minerals from those parts are omphacite and amphibole by means of EPMA and XRD.The results of XRD show that the order degree of albite is 1or very close to 1,so the albite is completely ordered or very close to be fully ordered,which indicates that the formation temperature of albite jade is very low.

Recently,several batches of CVD synthetic diamonds have been detected in NGTC laboratory.Identification characteristics of these CVD synthetic diamonds are obvious.Blue and orangy red fluorescence,blue phosphorescence and fine lamellar growth structure can be observed under DiamondViewTMand characteristic line at 737nm can be seen in the photoluminescence spectroscopy.These characteristics result from the growth conditions and mechanism.In this article,we took a CVD synthetic diamond found recently as an example,and reported the differences in the identification characteristics from the CVD synthetic diamonds tested before.The surface and internal characteristics of the sample were examined by using gemmological microscope and differential interference microscope.Fluorescence and phosphorescence of the CVD synthetic diamond were observed under 254nm(short wave)and365nm(long wave)ultraviolet radiation excitation,and UV fluorescence characteristics under DiamondViewTM(<230nm)were studied.Infrared absorption spectra of the sample were recorded,covering the mid-infrared spectral range(6 000~400cm-1,2cm-1 resolution)and near infrared spectral range(12 000~4 000cm-1,4cm-1resolution)at room temperature with the help of a Nicolet 6 700Fourier transform infrared spectrometer.We recorded photoluminescence spectra of the diamond at the temperature of liquid nitrogen,using a Renishaw 2000system with a 514.5nm Arion laser as the light source.It was also found that this sample displayed subtle layer growth characteristics and abnormal interference colours.Typical wide lamellar growth structures can be observed under DiamondViewTM.Boundary between layers is significantly clear,which can be seen under a gemmological microscope.The lamellar growth structures resulted from the variations of growth conditions and the discontinuous crystal growth during the processes.The discontinuity of the growth could lead to the dark carbon components with sp2 bonds on the(100)growing surface.Absorption lines at 7 354,6 856,5 563cm-1 concerned with hydrogen can be seen in the near infrared and mid-infrared spectra.It was reported that 8 753,7 354,6 856,6 425,5 563,3 123cm-1 peaks were detected in the NIR spectra in the CVD diamonds produced by American Apollo company,and those absorption peaks have been assigned to hydrogen impurity in the CVD synthetic diamonds,which were not found in the natural diamonds.After the high pressure and high temperature treatment,those absorption peaks would disappear,which indicate the sample has not undergone the HTHP treatment.In the photoluminescence spectra,N—V centers spectral lines located at 575,637nm and double lines of Si—V centers located at 737nm can be seen.The double lines at 737nm are a strong proof of CVD diamonds.Through the analysis of characteristics of the sample,it was understood that the CVD synthetic diamond grow in the multiple growth stages where the growth conditions could be slightly different.In a conclusion,the sample is considered as a CVD diamond product of early stage and has not undergone the HTHP treatment.

Early in 2012, NGTC labs in Shenzhen and Beijing investigated some naked and embedded diamonds which included some undisclosed CVD synthetic diamonds. It was found that these gem-quality CVD synthetic diamonds are difficult to distinguish from natural diamonds by normal micro-scopic observation. However, they can be effectively identified with the help of some advanced ana-lytical techniques, such as PL(Photolumineseence) and DiamondView^TM. The experiments show that the line at 737 nm in the PL spectrum and the bluish green fluorescence, the blue phosphores-cence together with characteristics of multi-layered structure in DamondViewTM are the characteris-tics of these CVD synthetic diamonds.

On the basis of lab researches performed in 2009 for the gemmological properties and compositions of peripheral materials of the red of Tibet,the investigation team of National Gemstone Testing Center,China(NGTC) performed a field investigation on occurrence of international disputing about red of Tibet from the geology,mineral deposit,stratigraphy and geomorphology at the border area between Bailang county and Jiangzi county in Shigatse,Tibet(E29°04′01.5″,N89°20′54.8″) in May,2010.The investigation team interviewed the villagers of Mencuo and Zhalin villages,viewed the trade process and collected the red feldspar samples.The results show that the majority of red feldspar samples in the field were artificially placed on the ground surface and in the loose ground,which supports the previous deduction of lab researches in 2009.

Since 2008,whether the "red feldspar from Tibet" exists and whether such a stone is diffusedly-treated have been hot-debated issues in the gemmology communities at home and abroad.The gemmological characteristics of the surrounding rocks and the surface residues of the "red feldspar from Tibet" are studied presently by using the polarizing microscope,electron microprobe and X-ray photoelectron spectroscopy techniques.The results show that the original host rocks of the "red feldspar from Tibet" are composed mainly of intermediate-basic intrusive rocks containing glasses and bubbles,and that the surface residues of the red feldspar and its surrounding rocks contain plenty of copper and iron.Furthermore,the surrounding rocks and surface residues may have artificially been sintered at a high temperature in their later development stage.In this sintering process,part of dark minerals and some foreign substances such as co-solvents turned into glasses and bubbles.Further tests reveal that the majority of the "red feldspar from Tibet" samples under investigation might have been copper-diffusedly-treated.