Abstract:The main mineral composition of Dahua nephrite is microcrystalline tremolite, and other minor minerals include calcite, diopside, apatite, quartz, chlorite, serpentine, talc, garnet and limonite. This study employed such means as orthogonal polarization microscope, electron microprobe analysis, X-ray powder diffraction and infrared spectrometer. The hardness, density, refractive index, compressive strength, tensile strength and toughness of the Dahua nephrite were determined. It is shown that the genetic type of the deposit belongs to stratabound and contact metasomatic type magmatic hydrothermal deposit, as shown by REE, hydrogen, oxygen and silicon isotope analysis. The mineralization age is 260 million years, as revealed by U-Pb zircon dating of diabase.

Abstract:Qinghai nephrite exhibits a rich variety of colors, of which the distinctive cyan and smoky-violet colors have not yet been found in other areas. In gemstone research, a consensus that cyan of the nephrite is caused by Cr³⁺ has been basically reached. However, there is less research on the cause of smoky-violet color. Thus, the authors went into the mining area and markets to collect a large number of smoky-violet nephrite samples. Using microscope, Raman spectrometer, UV-VIS micro spectrophotometer, EPMA and inductively coupled plasma mass spectrometry (ICP-MS), the authors have detected that the smoky-violet color is not caused by the chemical elements contained in the nephrite, but by the scattering of the incident light, which causes purple or gray tones, resulting from the abounding dark minerals such as graphite.

Abstract:Gemologists are attracted by Ximu jade from Ximu Town in Liaoning Province for its fine structure. In this study, microscope, XRD, EMPA, FTIR, Raman and XRF were used to investigate the jade. It is found that the Ximu jade is an almost monomineralic rock, consisting mainly of tremolite with fibrous interlock structure. The green color is related to the Fe ion:with the increase of Fe ion content, the color becomes darker.

Abstract:The identification of ancient nephrite skin color, impregnation and dying is an important reference for the dating of ancient jade. The identification of ancient jade in modern times is mainly based on archaeological excavation of the standard objects or reference to other artifacts of the same era. However, the skin color, impregnation and dying are the second chromosome of nephrite, and the causes are more complex. With the development of comprehensive scientific detection methods for nephrite skin color, impregnation and dying, jade researchers have achieved substantial achievements. In this paper, the authors investigated the ancient Chinese nephrite and, on the basis of research results of nephrite skin color, impregnation and dying in the history, discussed the application of mineralogical theory and scientific instrument testing methods.

Abstract:In this paper,infrared spectroscopic analysis,microscope and electron microprobe analysis were employed to study petrological and mineralogical characteristics of stony appearance portion in placer nephrite.The results show that stony appearance portion in placer nephrite mainly consists mainly of tremolite phenocryst and diopside with minor muscovite. According to the difference of mineral composition of stony appearance portion in placer nephrite, the stony appearance portion in placer nephrite can be divided into tremolite-type, tremolite-diopside type and diopside type. The development of stony appearance portion is related to the grain size and structure of minerals.

Abstract:Guangdong green jade, also known as Guangdong green or Xinnan jade, is produced in Guangning County of western Guangdong Province. It belongs to altered sericite jade and has abundant colors, such as green, white, yellow and black, with green being the main color. Guangdong green jade is an important kind of special jade material in southern China. However, studies of Guangdong green jade are relatively insufficient, and there are divergences on some problems, which severely restrict the scientific understanding of jade and jade development and utilization. With Guangdong green jade as the study object and by means of field investigations and modern testing methods such as petrographical observation, mineral chemical analysis and XRD, the authors made a systematic and detailed study concerning its mineral composition, chemical composition, petrological features, with the purpose of explaining coloring mechanism of Guangdong green jade.

Abstract:Guangdong green jade was found in Guangning County, western Guangdong Province. It belongs to altered sericite jade, with abundant colors such as green, white, yellow and black, with green being the main color. Transparency is an important parameter to evaluate the quality of a jade. Transparency of Guangdong green jade is generally low, mainly between the translucent and transparent type. A systematic experiment was designed for studying the factors controlling the transparency of Guangdong green jade. Based on the experimental results, it is suggested that the mineral structure of Guangdong green jade is crucial for the transparency. Impurities, cracks and colors also have some influence on transparency.

Abstract:Currently on the market, there are two kinds of yellow-green jade which are similar to turquoise "Rapeseed Yellow" varieties in appearance. The mineralogical, gemological, and spectral characteristics of the two kinds of yellow-green jade were studied by using slice observation, scanning electron microscopy, infrared spectrum, Raman spectroscopy and X-ray diffraction analysis. The results indicate that the main mineral components are alunite and apatite. The authors recommend the two kinds of yellow-green jade named apatite-alunite jade. In laboratory routine test, these jades can be distinguished from turquoise by appearance features, conventional gemological characteristics and infrared spectroscopy.

Abstract:Recently, the laboratory received a few pieces of jade samples whose appearance is very similar to that of nephrite. In order to better identify this kind of jade, the authors studied it by using conventional gemological methods and other methods such as thin section analysis, chemical analysis, infrared spectroscopy, X-ray diffraction analysis and Raman spectroscopy analysis. The results show that the main mineral composition of this jade is sillimanite,with a small amount of biotite and kaolinite. Its structure is prismatic and fibrous crystalloblastic texture distributed mainly in prismatic, fibrous and hairy forms. The black color of the sample may be caused by substitution of Fe³⁺ for Al³⁺ in the lattice. The more the Fe³⁺ content, the darker the color.

Abstract:China has large reserves of fluorites, and some of them display thermoluminescence. In this study, two pieces of natural luminescent fluorite were tested by inductively coupled plasma spectrometer and fluorescence spectrometer to reveal their chemical composition and emission spectra and investigated the luminescence mechanism. The results showed that the content of REE in natural luminescent fluorite was closely related to its luminescence. The richer the REE content of the sample, the stronger its luminescence. The emission peaks of the same sample differed when it was excited by different sources. Under high temperature source the main emission peaks were in the region of short wavelength. When the sample was excited by lower temperature source, the main emission peaks were in the region of long wavelength. The emission peaks were mainly related to Pr and Tb at high temperature, and some weak peaks were possibly caused by Ho. At lower temperature, the emission peaks were mainly related to Pr and Tb, and some weak peaks resulted possibly from Sm.

Abstract:In this study, a variety of albite jades, looking like jadeite with flower floating on ice on the market, were analyzed by conventional physical property testing, microscopy, electron microprobe, infrared spectroscopy and X-ray diffraction analysis, the chemical composition and mineral composition of this albite jade were determined, and the petrological and gemmological differences between the albite jade and jadeite were comparatively studied.

Abstract:This paper focuses on three purple chalcedony samples. In order to explore the color-forming mechanism of these samples, the authors used such means as polarizing microscope, EPMA, LA-ICP-MS, and UV-Vis spectroscopy. The images and the trace element analysis results were compared with previous studies. It is very probable that the color center caused the pattern for color formation. The formation of purple color was also influenced by trace elements and water in the samples.

Abstract:Amber usually varies from transparent to translucent. When a translucent amber looks white to yellow in color, it can be called the beeswax. Amber and beeswax almost have the same spectra, however, their appearance varies greatly. In this study, scanning electron microscopy (SEM), gem microscope and infrared spectroscopy were employed to investigate amber from Baltic Sea. Beeswaxed-amber and transparent amber show similar infrared spectra characteristics, suggesting that chemical composition is not the factor influencing their appearance. SEM images show that there are numerous bubbles on the surface of beeswaxed-amber. The diameters of the bubbles are generally less than 20 μm, with the majority around 5 μm. Combined with the microscopic observations, it is inferred that the appearance of the Baltic beeswax is related to the bubbles inside, and the beeswaxes with lower transparency and whiter color grade commonly contain much smaller and denser bubble inclusions.

Abstract:In this study, the authors investigated the distribution of Zn and Hg by using synchrotron micro X-ray fluorescence spectrum (SR-μXRF) along the growth circles of the golden-green and white pearls from Japanese Pinctada martensii. Both Zn and Hg concentrations represent the model of "low at first-high-low at last" along the growth rings in microscopic images of the pearl. SR-μXRF mapping images correspond to different periods:recuperating period, balanced period, and an abnormal high metabolism period between these two periods. The μ-XRF mapping data show a positive correlation of Zn and Hg:for the golden-green pearl, r=0.6; while for the white pearl, r=0.58, and the gold-green one has higher quality. Loading matrix of R type factors in the golden-green Japanese Pinctada martensii pearl reveals that the factors that influence element concentrations are biological growth support, environmental impact, and biomineralization. The fact that Zn has higher contribution to the factor of environmental impact reveals that Zn concentration depends on antagonism effect to a large extent. The results obtained by the authors have guiding significance for Pinctada martensii pearl culture.

Abstract:Blood Mila is a new kind of amber that has appeared on the market since last year, which has uncommon color and unique root-like inclusions (known as root-like patterns). There has been no definite conclusion about the genesis of such root-like inclusions so far. The root-like inclusions are extremely similar in morphology to the Lichtenberg figures in which the insulator initiates the generation of breakdown discharges through irradiation by electron beam technology. As insulators, whether amber and copal can generate Lichtenberg figures by the electron beam irradiation technology has not been reported yet. Therefore, the authors collected some amber and copal samples to perform electron beam irradiation test. The results show that the root-like inclusions can be generated in both amber and copal samples by the electron beam irradiation technology under appropriate process conditions. The root-like inclusions generated by irradiation are the dendritic channels with stress-related cracks generated by breakdown discharge in amber and copal samples, also named Lichtenberg figures. The root-like inclusions generated in tested samples by irradiation are almost the same in morphology as those in Blood Mila samples.

Abstract:Red coral has growth rings which can record the ecological environment information. In this study, the authors investigated the distribution of Ca, transition metal elements Mn, Fe, Cu and Zn, rare earth element Dy, and poison element Hg in the growth rings of red coral from Taiwan by synchrotron radiation micro X-ray fluorescence spectrum (SR-μXRF). The results showed that Ca changed with the periodic variation of life activities, Fe changed with the active degree of coral life. The distribution of Hg could reflect changes in the coral skeleton from larvae to adult. The authors analyzed the relationship between elements distribution in the growth rings of red coral's cross section and ecological environment, and then investigated the relationship between red coral's ecological environment and the marine environment; On such a basis, some information could be obtained concerning marine environment variation with time dimension.

Abstract:Ammolite is a kind of organic gemstone that often shows red, green and blue iridescence after coating. It is mainly obtained from iridescent fossilized ammonite shells mined in Alberta, Canada. In this paper, the authors studied the samples by conventional gemological testes,Raman spectrum, UV-Vis spectrum,and scanning electron microscope. The gemological characteristics, chemical composition, surface micro-topography and color origin were analyzed. The results show that the split and coated layer can be observed under the microscope. The surface colors in different areas of the ammonite are closely related to the layer structure. With thicker and tighter aragonite layers, the color of ammonite shifts toward longer wavelength in the visible region. According to the results obtained, the color of ammonite is probably caused by interference effect of the aragonite layers.

Abstract:Red corals are precious corals. Rare earth elements (REE) in red corals of different species harvested from different seas were investigated in this paper. REE accumulation is mainly affected by biological growth; ∑REE are low, and light rare earth elements are relatively enriched while heavy earth elements are relatively depleted; δCe values exhibit mainly negative anomalies, whereas δEu values show positive anomalies in some samples; REE characteristics of different red corals somewhat indicate the sea where they are harvested, and also show that the living environment of red corals is closely related to volcanic hydrothermal activities, which influence the source input of red coral growth. The ecological environment rareness contributes to the rareness of red corals.

Abstract:Amber is a kind of precious organic gem that has a long history of utilization as beads and jewelries. There are a lot of amber beads of West Han Dynasty to South & North Dynasty from archaeological sites in the collections of Yangzhou Museum, Hepu Museum and museums in Yunnan Province, Hunan Province and Hubei Province. Most of these amber beads have not been analyzed in lab. This study is focused on the identification of age, material and origin of amber beads through different analytical methods in lab. Methods of typology, outer characteristics analysis through magnifying glass and infrared spectrometer that is non-destructive were employed in the study of 4 pieces of ancient amber beads. The preliminary results show that 4 pieces of ancient samples from Beijing Bead Museum were probably the products of West Han to North & South Dynasty of China, and the material of these samples is amber and has the features of amber from Baltic Sea. This study also suggests that amber was probably an important commercial item of the marine silk road 2000 years ago.

Abstract:A purple pearl sample of Pinctada martensii, which shows color anomaly, was tested by means of synchrotron radiation X-ray fluorescence spectra, ultraviolet-visible spectra and Raman spectra, with the purpose of studying its color-forming mechanism. The results show that the purple pearl sample of Pinctada martensii was dyed on both surface and nucleus by inorganic dye, and hence its color is dyed.

Abstract:The corundum in Fuping area of Hebei Province was taken as the studied object to probe into the occurrence characteristics and genesis of migmatite corundum. The mineral paragenetic association, texture and paragenetic sequence of minerals of corundum were investigated by means of mineralogy, petrology and geochemistry, and the formation mechanism of corundum in this area was discussed. The size of the corundum is generally large, and the associated minerals are mainly K-feldspar, plagioclase, biotite, muscovite, sillimanite, rutile, chlorite, magnetite, ilmenite, and apatite. According to petrographic characteristics, it is inferred that the corundum was formed by crystallization of aluminum-rich magma in the process of migmatization. The gemological significance of the migmatite corundum was studied, and the result shows that the migmatite corundum can reach the gem grade, although it is difficult for this mineral to achieve the fine grade. The large-scale development and utilization of this mineral should implement targeted improvement and treatment.

Abstract:Silica aggregates formed at low temperature and low pressure (LTLP) are distributed widely in the world and have aroused more and more attention for their various applications in many fields. Silica phases that occur at LTLP include α-quartz, α-cristobalite, moganite and opal, often as various kinds of silica aggregates:opalline opal-A, cryptocrystalline opal-CT/C and chalcedony, cryptocrystalline-phanerocrystalline granulous quartz aggregates. These silica aggregates could exist in host rocks with different geneses; however, there still exist some discrepancies and regularities in their occurrence and distribution as well as types and ages of their host rocks, which can provide some guidance and reference not only for the development and utilization of these resources but also for the discussion of their genesis. In this paper, discrepancy and regularity were summarized based on the available references. Besides determinative influence of geological environment on the existing form and occurrence of silica aggregates, the environment plays an important role. Thus, we should combine paragenetic minerals which can reflect some information of geological activities to evaluate the existing form and occurrence of silica aggregates in specific regions.

Abstract:Dyed agate has been considered to be the optimal treatment for agate, and is acceptable by the customers. However, lots of media hold that dyed agate contains hazardous elements which are potentially harmful to people's health. In order to determine whether the agate from Dongpu of Xiamen and Boluo of Huizhou is harmful to people's health or not, the authors analyzed the hazardous elements and the dissolution hazardous elements in the agate bought from these two production and wholesale markets, and after the authors dyed the agate in the laboratory the hazardous elements were analyzed again. All the results show that the hazardous elements are under the limits, and hence should cause no harm to people's health.

Abstract:Petrologic and mineralogical characteristics of Yishui inkstones from Hebei Province were studied by using petrographic observation, electron microprobe analysis and X-ray powder diffraction. Yishui inkstones belong to clastic rocks. There are two species of Yishui inkstones, i.e., Yudai inkstone and Zicui inkstone. The main particles of Yudai inkstone consist of quartz, feldspar, hematite, and zeolite, whereas the cement consists of clay mineral illite, which accounts for 30~40 percent of the total content. The main particles of Zicui inkstone are composed of quartz, feldspar, hematite, zeolite and calcite, whereas the cement consists of clay minerals, such as illite, montmorillonite, chlorite, vermiculite and kaolinite. Clay minerals account for 30~50 percent of the total minerals.

Abstract:In this study, the authors investigated the radioactivity of 43 kinds of jewelry jades, such as diamond, corundum, tourmaline, emeralds, pearl and coral by means of multi-channel low background high-purity germanium gamma spectrometer so as to obtain natural radioactive nuclide activity values of ²²⁶Ra, ²³²Th, ⁴⁰K in these samples. The measurement data clearly show that all samples have very low levels of radioactive specific activity. I_Ra and I_γ of all the samples are far below the national limit of radioactivity in building materials. Artificial irradiated gemstones present a higher activity than almost all gemstones without irradiation.

Abstract:Mineralogical characteristics and ink-making mechanism of Hongsi inkstones from Linqu in Shandong Province were studied by means of petrographic observation, X-ray powder diffraction (XRD), and microhardness testing. By imitating the artificial ink-grinding, the authors designed an experiment to compare the difference between ink-makings, and quantitatively evaluated the advantages and disadvantages of the ink-making of inkstones by using slice observation creatively. The results show that quartz is the main functional mineral of the inkstones for ink-making, whereas the primary factor which influences the ink-making of the inkstones is the difference of quartz content and texture, such as roundness and grain size

Abstract:Previous geological work has found thousands of diamonds from Baiyan of Yimeng Mountain area, Shandong Province. These diamonds have plenty of green and green spots in crystals. The particles are fine, the surface has dark green or brown spots, and the color is uneven, exhibiting green, green, blue green, brown green, yellow green, gray green, or black green colors; the crystal is not complete, with light or micro wear. The green diamonds from the Shangnihecun conglomerate and the Quaternary fluvial sandstone and conglomerate of Zaozhuang City show a color pattern changing from green to brown. During the cutting and grinding process and the processing of green diamond with heating, the green color does not disappear, but the diamond changes in purity and brightness, or even shows new additional color or the disappearance of additional color. These changes are of gemological significance.

Abstract:In China, the consumption of gold jewelry has been increasing steadily over the past decades, which results in a constant strong demand. Gold resources can hardly meet the needs of the domestic market, and imbalance between supply and demand is becoming increasingly tense. It is the fact that China requires overseas gold resources. Under the guidance of environmental protection and sustainable development concept, it is essentially urgent to make best use of the advantages of domestic gold resources besides increasing the import of overseas gold resources. For the purpose of achieving the balance of gold demand and supply, the investigating of industrial alternatives for gold and taking active use of regenerated gold seem to be equally important.

Abstract:Wafangdian area of Liaoning Province is an important diamond-producing area in China. Since the important breakthrough made in the 1970s, the integration of the exploration and development has achieved remarkable economic and social benefits. Since the beginning of the 21^st century, the diamond industry development in the area has experienced a stagnant period. In recent years, the diamond exploration has made new progress. The innovation of system and mechanism and the construction of the diamond industry comprehensive park are important choices for ‘going out’ policy of China's diamond industry.