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《矿物岩石》2017,(3)
采用实验室常规检测方法和大型仪器测试技术(DiamondView~(TM)、红外光谱仪、激光拉曼光谱仪、X射线荧光光谱仪、电子探针、扫描电镜等),对充填处理碧玺的鉴定特征进行了深入的分析和研究。测试结果表明,市场上销售的经人工充填的碧玺中充填物主要为环氧树脂等高分子聚合物。经充填处理的碧玺,显微放大检查常可见充填物残余、气泡、流动构造等现象,裂隙出露表面处可见充填物与主体存在光泽差异。紫外荧光灯及DiamondView~(TM)下,充填物常沿裂隙或坑洞发出明显蓝白色荧光。红外光谱仪测试显示3 057cm~(-1),3 038cm~(-1),2 957cm~(-1),2 947cm~(-1),2 874cm~(-1),5 985cm~(-1),5 922cm~(-1),5 885cm~(-1)附近环氧树脂吸收峰。激光拉曼光谱仪测试显示1 112cm~(-1),1 185cm~(-1),1 608cm~(-1)组合的特征拉曼位移。扫描电镜测试中,充填物高分子聚合物在背散射电子像中为深灰色,面扫描测试显示充填处主要元素为碳(C),可指示有机充填物的存在。本文将充填处理单粒碧玺、珠串及群镶碧玺的充填程度与市场价值关系的研究成果及分级原则和方法进行了阐述。单粒碧玺中以充填裂隙的大小、形状、位置、数量、充填程度以及充填裂隙总和面积与样品最大截面积的占比,将其充填程度共划分为T0,T1,T2,T34个等级;珠串及群镶碧玺中以每一粒碧玺的充填等级,结合不同充填程度颗粒数量占整个样品颗粒数量的比例,将珠串及群镶碧玺共划分为TS0,TS1,TS2,TS34个等级。首次提出充填处理碧玺合格判定原则和定名表述形式。 相似文献
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目前主要通过放大检查和红外光谱分析等测试方法对有机充填碧玺进行鉴定,但它们在准确性和直观性方面还存在一些问题。为弥补现有方法的不足,利用DiamondView^TM荧光成像技术对有机充填处理的碧玺样品进行研究。结果显示,在DiamondView^TM下碧玺样品呈绿色或蓝色荧光,部分样品可观察到生长结构特征。分布于碧玺裂隙及凹坑内的有机充填物呈较强的蓝白色荧光,并与碧玺的荧光具有明显的差异和界限。利用DiamondView荧光图像分析,可以快速准确地识别充填物的位置及分布,也为碧玺在充填程度等方面的研究提供了新的思路。 相似文献
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利用激光诱导离解光谱自由定标法对一系列高纯度黄金样品进行定量分析与研究,初步证明了将此方法应用于黄金首饰成分测定的可行性。采用波长1 064nm的Nd∶YAG脉冲激光器激发黄金样品,波长范围为200～760nm的4CCD光纤光谱仪采集发射光谱,对Au元素质量分数范围为85.0%～99.6%的6件黄金标准样品进行激光诱导离解光谱测试。对所得黄金样品光谱中的Au,Cu,Ag三种元素分别选择合适的原子（离子）谱线代入自由定标法模型,通过所得参数拟合得到了所有元素原子（离子）的二维波尔兹曼平面曲线,并以此为基础进行元素的质量分数计算。激光诱导离解光谱自由定标法定量分析黄金样品中Au元素的质量分数与标准值的相对误差〈3%。 相似文献
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国家黄金钻石制品质量监督检验中心收到待检的百余件群镶钻石首饰中发现混有大量HPHT合成黄色钻石.采用宝石显微镜、红外光谱仪、X射线荧光光谱仪、紫外可见光分光光谱仪、紫外荧光灯、DiamondView^TM等对HPHT合成钻石样品做了详细地测试与分析.结果表明,这些HPHT合成钻石样品具有较为统一的黄色,放大检查可见合成钻石内部含有大量棒状、柱状、细小微粒状的铁镍合金包裹体,且几乎都有磁性,有些磁性甚至较强;样品的红外反射光谱非常特征,均具有明显的1 131 cm^-1处的吸收峰,为Ⅰb型钻石,而Ⅰb型钻石在天然钻石中极少见到;X射线荧光光谱测试显示有强烈的铁峰和镍峰,且在短波紫外线下多数具有绿黄色荧光.HPHT合成钻石在DiamondView^TM下具有不同程度的黄绿色荧光,部分具有黑十字现象. 相似文献
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采用常规宝石学鉴定方法、反光显微镜、X射线粉末衍射仪（XRD）、电子探针X射线显微分析仪（EPMA）、傅里叶变换红外光谱仪（FTIR）等测试方法,对山东昌乐蓝宝石砂矿中的一种副矿物样品进行了常规的宝石学、矿物学、谱学特征研究。肉眼观察,这种副矿物样品呈黑色、不透明,具有强磁性,摩氏硬度大于小刀。在反光显微镜下,该样品为钢灰色,呈现不透明的四边形颗粒状。X射线粉末衍射及电子探针成分分析的结果表明,该副矿物样品为富含Ti的磁铁矿,其晶体结构中类质同象替代广泛,但未见对人体有害的微量元素。该样品的红外光谱与磁铁矿的标准红外光谱基本一致。 相似文献
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针对客户声称的表面覆金刚石膜（DF）的合成立方氧化锆进行常规宝石学检测,结果发现,样品为覆膜合成立方氧化锆,但样品表面的覆膜层硬度低、光滑平整,与多晶金刚石膜的粒状结构及单晶金月1石膜表面定向排列的突起等特征均不相同。为了确定表面覆膜层的成分,采用小角X射线衍射仪、X射线光电子能谱仪和红外光谱仪对样品表面的覆膜层进行了物相分析、化学成分分析及谱学测试。X射线衍射分析表明样品表面的覆膜层属于非晶物相;X射线光电子能谱分析表明样品的膜层主要化学成分为C,F。结合薄膜材料资料分析,初步确定其表面覆膜层可能属于非晶氟化碳（a—C：F）膜;红外光谱分析结果显示样品表面的膜层所导致的1068cm-1处的特征峰,进一步验证了X射线衍射分析结论。综合结果表明,该样品表面的覆膜层为非晶氟化碳（a—C：F）膜,是一种仿金刚石膜。 相似文献
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广西大厂地区笼箱盖黑云母花岗岩与区内晚白垩世锡多金属成矿作用在时空上密切相关。岩相学特征表明,笼箱盖黑云母花岗岩中的电气石可以分为三类:1)浸染状电气石; 2)石英-电气石囊; 3)电气石-石英脉。本文利用电子探针和激光剥蚀等离子体质谱系统测定三种不同产状电气石的化学组成。分析结果显示,三种产状的电气石均具有高的Fe/(Fe+Mg)和Na/(Na+Ca)比值,主体属于碱基亚类铁电气石。浸染状电气石为岩浆晚期结晶,其Fe/(Fe+Mg)比值变化于0. 85～0. 94,随着岩浆分异,电气石逐渐富集Li、F、Fe和Sn等元素。与浸染状电气石相比,石英-电气石囊中早阶段电气石具有低的Fe/(Fe+Mg)比值,高的V、Co和Sr含量,可能反映了岩浆演化晚期出现的不混溶富硼熔/流体对早期黑云母和长石的交代作用,从而使囊中早阶段电气石继承部分被交代矿物的化学组成特征;石英-电气石囊中晚阶段电气石的化学组成变化较大(如Li、F、Mg、Al、V、Fe和Zn),与热液成因电气石的推论一致。与浸染状和囊状电气石相比,石英脉中的电气石具有高的Fe/(Fe+Mg)和Na/(Na+Ca)比值;微量元素组成与囊状电气石相似。就成矿元素锡而言,三种产状的电气石均具有相对高的锡含量,与其他地区锡成矿花岗岩中电气石的成分特征相似。但是,从岩浆晚期到热液阶段,大厂地区电气石的锡含量并没有显著升高,可能反映了早期岩浆热液流体对熔体锡有限的萃取作用。 相似文献
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《Chemie der Erde / Geochemistry》2023,83(1):125924
Two-mica granite is the most common magmatic rock type in the Himalayan leucogranite belt, which has close relationship with rare metal mineralization. Its genesis is generally attributed to magmatic differentiation. In recent years, the mineral geochemical compositions are increasingly used to study magmatic differentiation, which are significant for deciphering the melt evolution and element migration processes. In this study, in-situ major and trace element and boron isotope compositions for tourmalines from two-mica granites in the Cuona and Cuonadong leucogranites in the Cuona area are conducted to determine microscopic changes in mineral assemblages and geochemical compositions. Analytical results show that the tourmalines in the Cuonadong leucogranite were crystallized earlier relative to the tourmalines in the Cuona leucogranite during magmatic differentiation. The volatile contents have a genetic relationship with incompatible elements in tourmaline, which is possibly responsible for the formation of tourmaline zonation and the enrichment of Sr, Zn, and Pb during magmatic differentiation. The B isotopic composition of tourmaline in the Cuona area suggests that the granitic magma was dominantly derived from the partial melting of the metasedimentary source rocks. Their B isotope variations likely resulted from fluid exsolution during B-rich melt evolution. High rare metal contents in tourmalines indicate that the two-mica granites in the Cuona area may have great mineralization potential. 相似文献
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Tourmaline occurs as a minor but important mineral in the alteration zc,ne of the Archean orogenic gold deposit of Guddadarangavanahalli （G.R.Halli） in the Chitradurga greenst~ne belt of the western Dharwar craton, southern India. It occurs in the distal alteration halo of the G.R.Halli golcl deposit as （a） clusters of very fine grained aggregates which form a minor constituent in the natrix of the altered metabasalt （AMB tourmaline） and （b） in quartz-carbonate veins （vein tourmaline）. ~[＇he vein tourmaline, based upon the association of specific carbonate minerals, is further grouped as （i） albite-tourmaline-ankerite-quartz veins （vein-1 tourmaline） and （ii） albite-tourmaline-calcite-quartz veins （vein-2 tourmaline）. Both the AMB tourmaline and the vein tourmalines （vein-I and vein-2） belong to the alkali group and are clas- sified under schorl-dravite series. Tourmalines occurring in the veins are zoned while the AMB tour- malines are unzoned. Mineral chemistry and discrimination diagrams 1eveal that cores and rims of the vein tourmalines are distinctly different. Core composition of the ve：n tourmalines is similar to the composition of the AMB tourmaline. The formation of the AMB tourmaline and cores of the vein tour- malines are proposed to be related to the regional D1 deformational event associated with the emplacement of the adjoining ca. 2.61 Ga Chitradurga granite whilst rims of the vein tourmalines vis-a- vis gold mineralization is spatially linked to the juvenile magmatic accretion （2.56-2.50 Ga） east of the studied area in the western part of the eastern Dharwar craton. 相似文献
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A Comparison of In Situ Analytical Methods for Trace Element Measurement in Gold Samples from Various South African Gold Deposits 
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下载免费PDF全文 Christoph Gauert Mathias Schannor Lutz Hecht Martin Radtke Uwe Reinholz 《Geostandards and Geoanalytical Research》2016,40(2):267-289
Trace element concentrations in gold grains from various geological units in South Africa were measured in situ by field emission‐electron probe microanalysis (FE‐EPMA), laser ablation‐inductively coupled plasma‐mass spectrometry (LA‐ICP‐MS) and synchrotron micro X‐ray fluorescence spectroscopy (SR‐μ‐XRF). This study assesses the accuracy, precision and detection limits of these mostly non‐destructive analytical methods using certified reference materials and discusses their application in natural sample measurement. FE‐EPMA point analyses yielded reproducible and discernible concentrations for Au and trace concentrations of S, Cu, Ti, Hg, Fe and Ni, with detection limits well below the actual concentrations in the gold. LA‐ICP‐MS analyses required larger gold particles (> 60 μm) to avoid contamination during measurement. Elements that measured above detection limits included Ag, Cu, Ti, Fe, Pt, Pd, Mn, Cr, Ni, Sn, Hg, Pb, As and Te, which can be used for geochemical characterisation and gold fingerprinting. Although LA‐ICP‐MS measurements had lower detection limits, precision was lower than FE‐EPMA and SR‐μ‐XRF. The higher variability in absolute values measured by LA‐ICP‐MS, possibly due to micro‐inclusions, had to be critically assessed. Non‐destructive point analyses of gold alloys by SR‐μ‐XRF revealed Ag, Fe, Cu, Ni, Pb, Ti, Sb, U, Cr, Co, As, Y and Zr in the various gold samples. Detection limits were mostly lower than those for elements measured by FE‐EPMA, but higher than those for elements measured by LA‐ICP‐MS. 相似文献
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Katharina Marger Matthieu Harlaux Andrea Rielli Lukas P. Baumgartner Andrea Dini Barbara L. Dutrow Anne‐Sophie Bouvier 《Geostandards and Geoanalytical Research》2020,44(3):593-615
Six tourmaline samples were investigated as potential reference materials (RMs) for boron isotope measurement by secondary ion mass spectrometry (SIMS). The tourmaline samples are chemically homogeneous and cover a compositional range of tourmaline supergroup minerals (primarily Fe, Mg and Li end‐members). Additionally, they have homogeneous boron delta values with intermediate precision values during SIMS analyses of less than 0.6‰ (2s). These samples were compared with four established tourmaline RMs, that is, schorl IAEA‐B‐4 and three Harvard tourmalines (schorl HS#112566, dravite HS#108796 and elbaite HS#98144). They were re‐evaluated for their major element and boron delta values using the same measurement procedure as the new tourmaline samples investigated. A discrepancy of about 1.5‰ in δ11B was found between the previously published reference values for established RMs and the values determined in this study. Significant instrumental mass fractionation (IMF) of up to 8‰ in δ11B was observed for schorl–dravite–elbaite solid solutions during SIMS analysis. Using the new reference values determined in this study, the IMF of the ten tourmaline samples can be modelled by a linear combination of the chemical parameters FeO + MnO, SiO2 and F. The new tourmaline RMs, together with the four established RMs, extend the boron isotope analysis of tourmaline towards the Mg‐ and Al‐rich compositional range. Consequently, the in situ boron isotope ratio of many natural tourmalines can now be determined with an uncertainty of less than 0.8‰ (2s). 相似文献
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电气石岩是一种富硼的硅质喷气岩,主要产于以沉积岩为容矿岩石的喷气矿床中及附近。研究广泛认为其与喷流-沉积型块状硫化物矿床(SEDEX矿床)有着密切的关系,并被视为该类矿床找矿勘探的标志岩性之一。综述了电气石岩的产出环境、形态、岩石学、地球化学等地质特征,分析了电气石岩的沉积环境及成因。以澳大利亚布罗肯希尔地区电气石岩与矿化的关系为例,对其地质找矿意义进行了总结与展望。 相似文献
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Tourmalinites from the stratiform peraluminous metamorphic suite of the Central Namaqua Mobile Belt (South Africa) 总被引：1，自引：0，他引：1
A. P. Willner 《Mineralium Deposita》1992,27(4):304-313
Tourmalinites as proximal fades equivalents of stratiform peraluminous metamorphic rocks occur stratigraphically below base metal deposits and above thick metarhyolite horizons. Their premetamorphic protoliths are believed to have originated by tourmaline precipitation from exhalative B-, F- and W-rich brines also transporting aluminous clay colloids and dissolved silica. Tourmaline chemistry is used as an effective petrogenetic sensor. The tourmalines are Al-saturated, alkali-deficient dravite-schorl solid solutions, which are in the compositional range of tourmalines originated by exhalative processes. F-substitution in tourmalines is governed by Fe-F-avoidance. F is relatively enriched in the tourmalines and can potentially be used as a tracer for the source of primary hydrothermal solutions. Ti is introduced into the tourmalines by the substitution scheme Ti+AlIV=AlY+Si. The high Ti-contents of the tourmalines as well as those of coexisting muscovites represent evidence of high-temperature metamorphism. Many tourmalines exhibit continuous zoning, which can partly be attributed to external fluid influx near peak metamorphic conditions. 相似文献
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The first part of this paper presents chemical analyses and physical properties for 12 tourmalines of varying color, 10 samples from Mozambique, one from Afghanistan and one from Madagascar. The data are summarized in Tables 1–3. The second part reviews the isomorphism in the tourmaline group on the basis of data gathered from the literature. Plots of c0 against a0 for 198 X-rayed tourmalines and of (Fe, Mn, Mg, Ti) against the unit cell volume of 57 analyzed and X-rayed tourmalines supplement Epprecht's review. 相似文献