The high pressure and high temperature（HPHT） method is successfully used to synthesize jadeite in a temperature range of 1000℃–1400℃ under a pressure of 3.5 GPa. The initial raw materials are Na2SiO3·9H2O an...The high pressure and high temperature（HPHT） method is successfully used to synthesize jadeite in a temperature range of 1000℃–1400℃ under a pressure of 3.5 GPa. The initial raw materials are Na2SiO3·9H2O and Al2（SiO3）3.Through the HPHT method, the amorphous glass material is entirely converted into crystalline jadeite. We can obtain the good-quality jadeite by optimizing the reaction pressure and temperature. The measurements of x-ray diffraction（XRD）,scanning electron microscopy（SEM）, Fourier-transform infrared（FTIR） and Raman scattering indicate that the properties of synthesized jadeite at 1260℃ under 3.5 GPa are extremely similar to those of the natural jadeite. What is more, the results will be valuable for understanding the formation process of natural jadeite. This work also reveals the mechanism for metamorphism of magma in the earth.展开更多
Garnet is an important rock forming mineral of high pressure and ultrahigh pressure metamorphic rocks. Its popular isomorphism complicates its chemical composition and crystal structure. The selected area electron ...Garnet is an important rock forming mineral of high pressure and ultrahigh pressure metamorphic rocks. Its popular isomorphism complicates its chemical composition and crystal structure. The selected area electron diffraction (SAED) and the high resolution electron microscopy (HREM) are used in this work to study the microstructures and ultrastructures of garnets in the jadeite quartzite from Dabie Mountains, China. The microstructures of the garnet occur mainly as free dislocations, dislocation walls, stacking faults, dislocation networks and sub grain boundaries. The dislocation density is ρ=n ×10 8/cm 2 ( n =1.7—7.5) and the deformation mechanism is the dislocation glide and dynamic recovery. The superstructures of the garnet crystal revealed by HREM occur mainly as dislocations, faults, domain structures and lattice deformations, indicating the strong stress during the formation of the jadeite quartzite.展开更多
Fluid inclusions at a nano to sub-micron scale in quartz from jadeite quartzite at Shuanghe, Dabie Mountains, have been investigated by using the transmission electron microscopy (TEM). Most fluid inclusions are spher...Fluid inclusions at a nano to sub-micron scale in quartz from jadeite quartzite at Shuanghe, Dabie Mountains, have been investigated by using the transmission electron microscopy (TEM). Most fluid inclusions are spherical or negative crystal shaped, forming wide swarm-like trails. The TEM reveals that the relationship between coesite and the host quartz is syntaxic and provides strong evidence of the occurrence of high-salty fluids at peak metamorphic conditions. The fluid inclusions are often connected to dislocations, which are undetected at the scale of optical microscopy. Non-decrepitation leakage of fluid inclusions may occur by pipe diffusion of molecule H2O or CO2 along dislocations from the inclusions into the host quartz, thus leading to original inclusion density and composition changes. It should be taken into full account for the correct petrological interpretation of micro-thermometric results.展开更多
We tested 288 pieces of the polished cabochon jadeite-jade with high quality green and smooth surfaces using the colorimeter Color i5 based on the CIE 1976 L＊a＊b＊ uniform color space. The color changes after altern...We tested 288 pieces of the polished cabochon jadeite-jade with high quality green and smooth surfaces using the colorimeter Color i5 based on the CIE 1976 L＊a＊b＊ uniform color space. The color changes after alternating three CIE standard light sources D65, A and CWF were compared, and the degree of metamerism was evaluated. The results show that the CIE standard light sources D65, A and CWF increase the chroma of green and turn bluish green into vivid green, which are similar or to nearly colorless and transparent glass-like samples with fine textures. When the three light sources were individually alternated, the lightness of the jadeite-jades showed little change, but the tone changed significantly. Metamerism occurred only in 3 pairs among the 16 samples that were selected by cluster analysis for quality, and the metamerism colors were highly consistent of L＊D65∈（43.47, 46.75）, C＊D65∈（65.20, 68.80） and ho＊D65∈（138.10, 140.23）. We can conclude that the jadeite-jade green gradually turns to blue when the color temperature of the light source increases. But when considering both the light sources and the samples, D65 is more suitable to be the light source of jadeite-jade green when compared with the light sources CWF and A. Compared with the CIE standard green and high chroma green, high-quality jadeite-jade green has a slight yellow tone, low lightness and high chroma. The special metamerism index decreased to 1 when the light source alternated among D65, A and CWF. Therefore, the color of jadeite-jade green might be slightly influenced by alternating of the light sources.展开更多
In order to make more available methods for natural jadeite quality evaluation,this study applied rigorous coupled wave theory to calculate and simulate the reflection characteristics of various natural jadeites,and e...In order to make more available methods for natural jadeite quality evaluation,this study applied rigorous coupled wave theory to calculate and simulate the reflection characteristics of various natural jadeites,and establish evaluation standard based on the relationship between refractive index and reflectivity and responses of reflection efficiency to refractive index,grating thickness and incident angles,etc.The results suggest that reflection efficiency varies significantly as a function of the natural jadeite quality,which can provide a new method to evaluate natural jadeite.展开更多
The chroma difference(DC) and lightness difference (DL) of 288 jadeite-jades with fine texture and even green color have been analyzed based on color difference formula CIE LAB in the uniform color space CIE 1976 L^~*...The chroma difference(DC) and lightness difference (DL) of 288 jadeite-jades with fine texture and even green color have been analyzed based on color difference formula CIE LAB in the uniform color space CIE 1976 L^~*a^~*b^~* to evaluate their contribution to the color appearance and color difference(DE).The analysis of lightness(L^~*), chroma(C^~*) and hue-angle(h_o) show that the vivid yellowish green color occurs when L^~*∈5.29-59.2,展开更多
Hydrogen incorporation is critical for explaining defect energies, structure parameters and other physical characteristics of minerals and understanding mantle dynamics. This work analyzed the hydrogen complex defects...Hydrogen incorporation is critical for explaining defect energies, structure parameters and other physical characteristics of minerals and understanding mantle dynamics. This work analyzed the hydrogen complex defects in jadeite by the plane-wave pseudo-potential method based on density functional theory, and optimized the atomic positions and lattice constants in all configurations （different defective systems）. Incorporation mechanisms considered for hydrogen （H） in jadeite include： （1） hydrogen incorporating with the 02 site oxygen and coexisting with M2 vacancy; （2） one H atom combined with an AI atom replacing Si in tetrahedron; （3） 4H atoms directly replacing Si in tetrahedron and （4） 3H atoms replacing Al on the M1 site. The four incorporation mechanisms mentioned above form the corresponding VNa-Hi, Alsi-Hi, Vsi-4Hi and VAr3Hi point defects. The molecular dynamics simulation to the ideal, VNa-Hi, Alsi-Hi, Vsi-4Hi and VAr3Hi point defects under the P-T conditions of 900 K, 2 GPa, the Vsa-Hi and Alsi-Hi point defects under different pressures at T = 900 K, and Alsj-Hj point defects under different temperatures at P = 3 GPa was performed to examine the preferential mode of hydrogen incorporation in jadeite by means of first-principles calculations. The calculations show that the averaged O-H bond-length in the hydrogen point defects system decreased in the order of Alsi-Hi, VNa-HI, Vsl-4Hf and VAI-3Hi. VNa-HI complex defects result in a contraction of the jadeite volume and the presence of Alsi-Hi, Vsi-4H~ and VAI-3Hi defects could increase the superceli volume, which is the most obvious in the VAt-3Hi defects. The energy of formation of Also-HI and VA[-3HI complex defects was much lower than that of other defect systems. The VAI-3Hi defects system has the lowest energy and the shortest O-H bond-length, suggesting that this system is the most favorable. The analytical results of vacancy formation energy, O-H bond- length, and the stability of the hydrogen defects in jadeite have suggested that the preferred hydration incorporation mode in jadeite is VAI-3Hi complex defect.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.51172089 and 51171070)the Graduate Innovation Fund of Jilin University,China(Grant No.2016065)
文摘The high pressure and high temperature（HPHT） method is successfully used to synthesize jadeite in a temperature range of 1000℃–1400℃ under a pressure of 3.5 GPa. The initial raw materials are Na2SiO3·9H2O and Al2（SiO3）3.Through the HPHT method, the amorphous glass material is entirely converted into crystalline jadeite. We can obtain the good-quality jadeite by optimizing the reaction pressure and temperature. The measurements of x-ray diffraction（XRD）,scanning electron microscopy（SEM）, Fourier-transform infrared（FTIR） and Raman scattering indicate that the properties of synthesized jadeite at 1260℃ under 3.5 GPa are extremely similar to those of the natural jadeite. What is more, the results will be valuable for understanding the formation process of natural jadeite. This work also reveals the mechanism for metamorphism of magma in the earth.
基金This paperis supported by the National Natural Science Foundation of China( No.49872 0 69)
文摘Garnet is an important rock forming mineral of high pressure and ultrahigh pressure metamorphic rocks. Its popular isomorphism complicates its chemical composition and crystal structure. The selected area electron diffraction (SAED) and the high resolution electron microscopy (HREM) are used in this work to study the microstructures and ultrastructures of garnets in the jadeite quartzite from Dabie Mountains, China. The microstructures of the garnet occur mainly as free dislocations, dislocation walls, stacking faults, dislocation networks and sub grain boundaries. The dislocation density is ρ=n ×10 8/cm 2 ( n =1.7—7.5) and the deformation mechanism is the dislocation glide and dynamic recovery. The superstructures of the garnet crystal revealed by HREM occur mainly as dislocations, faults, domain structures and lattice deformations, indicating the strong stress during the formation of the jadeite quartzite.
基金the financial support from the National Natural Science Foundation of China grants(Nos.40272083 , 40172019) the Hubei Province Natural Science Foundation ofChina grant(No.2002ABO20).
文摘Fluid inclusions at a nano to sub-micron scale in quartz from jadeite quartzite at Shuanghe, Dabie Mountains, have been investigated by using the transmission electron microscopy (TEM). Most fluid inclusions are spherical or negative crystal shaped, forming wide swarm-like trails. The TEM reveals that the relationship between coesite and the host quartz is syntaxic and provides strong evidence of the occurrence of high-salty fluids at peak metamorphic conditions. The fluid inclusions are often connected to dislocations, which are undetected at the scale of optical microscopy. Non-decrepitation leakage of fluid inclusions may occur by pipe diffusion of molecule H2O or CO2 along dislocations from the inclusions into the host quartz, thus leading to original inclusion density and composition changes. It should be taken into full account for the correct petrological interpretation of micro-thermometric results.
基金financial support by "the Fundamental Research Funds for the Central Universities"
文摘We tested 288 pieces of the polished cabochon jadeite-jade with high quality green and smooth surfaces using the colorimeter Color i5 based on the CIE 1976 L＊a＊b＊ uniform color space. The color changes after alternating three CIE standard light sources D65, A and CWF were compared, and the degree of metamerism was evaluated. The results show that the CIE standard light sources D65, A and CWF increase the chroma of green and turn bluish green into vivid green, which are similar or to nearly colorless and transparent glass-like samples with fine textures. When the three light sources were individually alternated, the lightness of the jadeite-jades showed little change, but the tone changed significantly. Metamerism occurred only in 3 pairs among the 16 samples that were selected by cluster analysis for quality, and the metamerism colors were highly consistent of L＊D65∈（43.47, 46.75）, C＊D65∈（65.20, 68.80） and ho＊D65∈（138.10, 140.23）. We can conclude that the jadeite-jade green gradually turns to blue when the color temperature of the light source increases. But when considering both the light sources and the samples, D65 is more suitable to be the light source of jadeite-jade green when compared with the light sources CWF and A. Compared with the CIE standard green and high chroma green, high-quality jadeite-jade green has a slight yellow tone, low lightness and high chroma. The special metamerism index decreased to 1 when the light source alternated among D65, A and CWF. Therefore, the color of jadeite-jade green might be slightly influenced by alternating of the light sources.
文摘In order to make more available methods for natural jadeite quality evaluation,this study applied rigorous coupled wave theory to calculate and simulate the reflection characteristics of various natural jadeites,and establish evaluation standard based on the relationship between refractive index and reflectivity and responses of reflection efficiency to refractive index,grating thickness and incident angles,etc.The results suggest that reflection efficiency varies significantly as a function of the natural jadeite quality,which can provide a new method to evaluate natural jadeite.
文摘The chroma difference(DC) and lightness difference (DL) of 288 jadeite-jades with fine texture and even green color have been analyzed based on color difference formula CIE LAB in the uniform color space CIE 1976 L^~*a^~*b^~* to evaluate their contribution to the color appearance and color difference(DE).The analysis of lightness(L^~*), chroma(C^~*) and hue-angle(h_o) show that the vivid yellowish green color occurs when L^~*∈5.29-59.2,
基金supported by the National Natural Science Foundation of China (grants No.41172051 and 41472042)the Specialized Research Fund for the Doctoral Program of Higher Education of China (grant No.20060491504)
文摘Hydrogen incorporation is critical for explaining defect energies, structure parameters and other physical characteristics of minerals and understanding mantle dynamics. This work analyzed the hydrogen complex defects in jadeite by the plane-wave pseudo-potential method based on density functional theory, and optimized the atomic positions and lattice constants in all configurations （different defective systems）. Incorporation mechanisms considered for hydrogen （H） in jadeite include： （1） hydrogen incorporating with the 02 site oxygen and coexisting with M2 vacancy; （2） one H atom combined with an AI atom replacing Si in tetrahedron; （3） 4H atoms directly replacing Si in tetrahedron and （4） 3H atoms replacing Al on the M1 site. The four incorporation mechanisms mentioned above form the corresponding VNa-Hi, Alsi-Hi, Vsi-4Hi and VAr3Hi point defects. The molecular dynamics simulation to the ideal, VNa-Hi, Alsi-Hi, Vsi-4Hi and VAr3Hi point defects under the P-T conditions of 900 K, 2 GPa, the Vsa-Hi and Alsi-Hi point defects under different pressures at T = 900 K, and Alsj-Hj point defects under different temperatures at P = 3 GPa was performed to examine the preferential mode of hydrogen incorporation in jadeite by means of first-principles calculations. The calculations show that the averaged O-H bond-length in the hydrogen point defects system decreased in the order of Alsi-Hi, VNa-HI, Vsl-4Hf and VAI-3Hi. VNa-HI complex defects result in a contraction of the jadeite volume and the presence of Alsi-Hi, Vsi-4H~ and VAI-3Hi defects could increase the superceli volume, which is the most obvious in the VAt-3Hi defects. The energy of formation of Also-HI and VA[-3HI complex defects was much lower than that of other defect systems. The VAI-3Hi defects system has the lowest energy and the shortest O-H bond-length, suggesting that this system is the most favorable. The analytical results of vacancy formation energy, O-H bond- length, and the stability of the hydrogen defects in jadeite have suggested that the preferred hydration incorporation mode in jadeite is VAI-3Hi complex defect.
