共查询到18条相似文献，搜索用时 718 毫秒
1.
再生钻石是使用化学气相沉积法(CVD)以天然钻石为基底再生长合成钻石层,得到具有整体外观的钻石产品。由于再生钻石含有天然钻石的氮杂质信息,传统的合成钻石排查方法和检测流程已不再适用于再生钻石的检测。本文对实验室检出的一颗再生钻石进行了详尽的宝石学测试分析,以建立再生钻石的最佳检测方案。结果显示:常规的显微观察、钻石仪器排查以及红外光谱测试都不能将再生钻石检出。DiamondViewTM多方位发光图像观察该样品呈现清晰的发光分层现象,上层为红色荧光与蓝绿色磷光,下层为深蓝色荧光与惰性磷光;红外透射光谱分区域定点扫描样品上层为IIa型钻石,下层为Ia型钻石;紫外可见吸收光谱分析和光致发光光谱测试显示样品同时具有N3和高浓度[Si-V]-缺陷。综合判定该样品亭部的下半部分为天然钻石,亭部的上半部分和冠部为CVD合成钻石,CVD层厚度约740μm。作为我国首例报道的再生钻石,与国外已报道的同类型样品相比,该样品中分层界限不可见,且合成层厚度呈现明显增长。研究认为,应用多方位发光图像分析及光谱测试技术是再生钻石检测的关键。 相似文献
2.
新型GV5000宽频诱导发光测试仪的研制及其应用于筛分无色小颗粒合成钻石和天然钻石 总被引：1，自引：1，他引：0
天然钻石中普遍含有聚合氮以及复杂的生长结构,而合成钻石不含氮或含少量单氮并有典型的与合成条件有关的生长结构,利用此类性质可对天然和合成钻石进行区分。但对粒度细小或镶嵌复杂的钻石样品进行检测时,现有仪器由于局限性难以实现有效测量。本文研制了一种新型宝石发光性测试装置——宽频诱导发光测试仪(GV5000),通过对激发光源和滤光片、结构设计和测试方式的研发,实现了可同时观察多个小颗粒样品(最小为0.002 ct)的荧光特征和磷光特征,建立了一种以发光特征差异性作为筛分条件快速、准确筛分无色小颗粒天然钻石和合成钻石的分析方法。应用本方法测试了9015粒样品,并通过红外光谱、光致发光光谱等方法对筛查结果进行验证,表明97%的天然钻石具有蓝白色荧光并无磷光,而合成钻石的发光特征明显区别于天然钻石。本方法避免了样品大小和形状的影响,提高了小颗粒钻石鉴定的准确度和检测效率,对天然钻石的筛查率可达97%,对合成钻石的筛查率可达100%。 相似文献
3.
最近NGTC实验室检测出多批次CVD合成钻石,这些CVD合成钻石均具有明显的鉴定特征,使用钻石观测仪（DiamondViewTM）观察可见蓝色、橙红色荧光和蓝色磷光以及细密层状生长纹理,光致发光光谱中可见737 nm处的特征发光线.这些特征均与其生长结构及生长过程中进入钻石晶体中的杂质有关.笔者以最近检测过程中发现的一颗CVD合成钻石为例,使用高倍率显微技术对其层状结构的微细特征及其在钻石观测仪下的荧光特征的关系进行了详细观察和对比.结果显示,此样品与之前检测到的CVD合成钻石略有差异.此次检测到的样品在钻石观测仪（DiamondViewTM）下观察具有较宽的层状生长分区,层与层之间的分界线十分明显且在高倍显微镜下也可见到细微的生长特征.通过对样品特征的分析,了解了晶体生长过程中多阶段生长条件的变化,更直观的展现了CVD合成钻石的生长过程. 相似文献
4.
为了从动态过程中更直观地研究黄色高温高压合成钻石的颜色成因和改色机理,本文对5颗黄色高温高压合成钻石进行高温高压改色实验,并对样品改色前后的红外光谱、光致发光光谱、DiamondViewTM图像进行了分析,发现受合成方法限制,高温高压法合成钻石所含缺陷较多,除应力缺陷外,还含有较多空穴和杂质元素,如N、Ni等,对合成钻石的品质和颜色有较大影响。同时,通过红外光谱和光致发光光谱测试得到,改色前、后合成钻石样品内的色心包括(N_V)-、(N_V)、H3、C心、(Ni_V)-、Ni_N复合体和Ni-。实验所提供的7 GPa高压及1 480℃高温条件有助于钻石晶体内部氮的聚集,从而改变合成钻石的类型,即由Ⅰb型(含少量A集合体)转变为Ⅰb+ⅠaA混合型,同时对合成钻石的颜色也产生了影响。 相似文献
5.
为了提高批量小颗粒钻石的筛查效率和准确性,研制了一种新型紫外光致发光图像高速采集装置——珠宝首饰观察鉴定仪(DDO),通过对激发光波长、工业相机等的选用和结构设计技术突破,以及对发光现象采集方式进行创新,实现了批量观察不同宝石间的光致发光现象和发光延迟现象差异等,从而实现对宝石高效检测。对20 000粒以上无色天然钻石、合成钻石和钻石相似品进行的DDO测试结果表明,98%~99%的无色天然钻石在紫外光激发光停止后的0.1~10 ms内可观察到的碧蓝色磷光现象,为天然钻石典型特征,合成钻石和其他无色宝石的发光特征(发光颜色、强度、持续时间、结构分区)明显区别于天然钻石,由此建立了一种通过观测包括荧光、衰减时间在100 ms内的连续发光(磷光)特征差异性作为筛分条件快速、准确筛分无色天然钻石的新方法。本装置提高了钻石鉴定的准确度和检测效率,对天然钻石的筛查通过率可高达99%,对合成钻石和仿钻石的筛查准确性可达100%。 相似文献
6.
无色-近无色高温高压合成钻石的谱图特征及其鉴别方法 总被引：4，自引：4，他引：0
实验室发现大量小颗粒的无色高温高压(HPHT)合成钻石与天然钻石混杂镶嵌在各种饰品中,前人提出荧光和磷光特征是主要的快速区分特征,然而荧光、磷光特征的差异并不能完全将HPHT合成钻石与天然钻石区分开来。本文将常规的宝石学观察分析与多种高精度谱学测试相结合,对五粒不同的无色-近无色HPHT合成钻石样品进行深入研究。结果表明,五粒钻石在紫外可见吸收光谱无270 nm吸收或是只有极弱的270 nm吸收,随着颜色级别的降低,270 nm吸收越明显。红外光谱测试显示,各粒样品中都含有不等量的硼元素。光致发光光谱测试表明,HPHT合成钻石含有与微量N、Ni、Si等相关的晶格缺陷。超短波紫外光源激发下,所有的HPHT合成钻石都有强磷光,在钻石观察仪下可以观测到清晰的八面体和立方体分区特征。显然,不同的合成钻石的特征略有差异,但综合其荧光及磷光特征以及红外、紫外、光致发光光谱特征,可以准确地将无色HPHT合成钻石与对应的天然钻石区分开来。 相似文献
7.
大别山榴辉岩带片麻岩的锆石拉曼光谱研究 总被引：4，自引：0，他引：4
我们对来自大别山榴辉岩带11个片麻岩样品的锆石进行了拉曼光谱研究,这些研究集中在1008和356cm~(-1)峰和它们的半高宽上。依据阴极发光(CL)图像特征,锆石可分为三种结构类型:(1)核边结构,由一个老的岩浆锆石核和一个变质边构成,也可由两期变质锆石构成;(2)CL 不均匀强反差发光的锆石,这些锆石的一些部位明显发亮,这些发亮的部分是在早期岩浆锆石发育而来的;(3)CL 总体是均匀的或弱反差发光锆石。在 CL 图像的基础上,我们用拉曼扫描的方法分析了这3类不同结构的锆石。1008和356cm~(-1)峰显示了相同或相似的图像特征,而它们的半高宽图像有相同或相似的图像特征。峰和半高宽图像可以有一定差异。核边结构的和 CL 不均匀强反差发光的锆石的 CL 结构也反映在拉曼光谱的图像上,半高宽的图像更相似于锆石的 CL 图像。CL 总体是均匀的或弱反差发光锆石的拉曼光谱图像通常也是相对均匀的。11个样品锆石的1008cm~(-1)峰位值和它的半高宽落在放射破坏趋势上,我们认为早期继承的锆石在超高压变质过程中发生了完全退火和重结晶。一粒锆石拉曼光谱图像的结构反映的是不同的部分蜕晶化程度的差异,由于有相同的蜕晶化历史,这些部分的蜕晶化程度与这些部分的 U 和 Th 含量应该是正相关的。 相似文献
8.
Chameleon钻石（俗称“变色龙钻石”）是一种具有光致变色和热致变色现象的彩色钻石,在受热后或长时间在暗室中会由黄绿色变为黄色,在实际工作中发现与Chameleon钻石颜色相似的黄色钻石并不具有此类“变色”现象。为了研究Chameleon钻石与相似黄色钻石的差异,并进一步探究产生光致变色和热致变色现象的原因,本文选取Chameleon钻石和与其颜色相似的黄色钻石作为研究对象,进行加热实验,观察加热前后钻石颜色、紫外可见光吸收光谱的变化情况,探寻导致热致变色的原因,并对样品的红外吸收光谱及光致发光光谱特征进行详细分析与比较。结果表明：Chameleon钻石受热后由黄绿色变为黄色,在超短波紫外线下显示绿色荧光和磷光,相似黄色钻石样品无磷光及变色现象;所有样品均有从紫外光至510nm逐渐减弱的连续吸收和480nm吸收宽带,Chameleon钻石具650～800nm吸收宽带,相似黄色钻石无该吸收带,加热后吸收带消失是其产生热致变色的主要原因;进一步对样品的缺陷类型进行对比分析,Chameleon钻石红外光谱可见孤氮特征及与片晶无关的1430cm-1宽吸收带,该峰未在相似黄色钻石中出现,但产... 相似文献
9.
采用显微观察、红外光谱、可见吸收光谱和低温光致发光谱等分析方法,对9颗俄罗斯高温高压处理钻石样品进行了研究。结果表明,该类钻石样品的内部多见石墨化现象,尤以彩色钻石样品更明显;金黄色、紫红色、黄绿色样品为ⅠaAB型,浅黄色样品为ⅠaB型,近无色样品为Ⅱa型;样品的可见吸收光谱因颜色不同而差异显著,其中金黄色样品可见475 nm处的吸收宽带,紫红色样品可见638,614,595 nm处的吸收峰,黄绿色和浅黄色样品可见415,475,503 nm处的吸收峰,近无色样品则为较光滑的平直曲线。此外,该类样品在低温光致发光谱中可见575 nm与637 nm处强发光峰。这些特征为探讨该类钻石的晶格缺陷与呈色机理提供了一定的科学依据。 相似文献
10.
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
11.
山东蒙阴金刚石的形成时代及地质环境 总被引：4，自引：0，他引：4
对山东蒙阴胜利1号岩管的金刚石样品进行了CL、FTIR、RAMAN等测试。结果表明,除部分样品阴极发光显示平直的生长色带外,多数金刚石显示均一的CL颜色,说明金刚石生长过程连续,未遭受明显的溶(熔)蚀,不同于复县的多数金刚石。依据金刚石中N的聚集状态,估算了蒙阴金刚石主要形成于三个时期:1·8~1·7 ,1·3 ~1·1和0·9 ~0·6 Ga。有意义的是,这三个时期与华北克拉通三次伸展事件时间相吻合。通过金刚石中橄榄石包裹体拉曼漂移,计算出源区压力为4·6 ,5和5·5 GPa ,得出蒙阴金刚石形成的深度分别为:152 ,165和181 km,靠近岩石圈底部。上述成果为蒙阴金刚石的形成提供了时间、空间、压力等重要地质信息。 相似文献
12.
Wuyi Wang Shigeho Sueno Eiichi Takahashi Hisayoshi Yurimoto Tibor Gasparik 《Contributions to Mineralogy and Petrology》2000,139(6):720-733
Trace element concentrations of peridotitic garnet inclusions in diamonds from two Chinese kimberlite pipes were determined
using the ion microprobe. Garnet xenocrysts from the same two kimberlite pipes were also analyzed for comparison. In contrast
to their extremely refractory major element compositions, all harzburgitic garnets showed enrichment in light rare earth elements
(REE) relative to chondrite, resulting in sinuous REE patterns. Both normal and sinuous REE patterns were observed from the
lherzolitic garnets. Concentrations of REE in garnets changed significantly from diamond to diamond and no specific correlations
were observed with their major element compositions. Analyses of randomly selected two to three points within every grain
of a large number of garnet inclusions by the ion microprobe demonstrated that there was no evident compositional heterogeneity,
and multiple grains of one phase from a single diamond host also exhibit very similar compositions. This implies that the
trace element heterogeneity within one grain or among multiple inclusions from the same diamond host, as reported from Siberian
diamonds, is not a common feature for these Chinese diamonds. Concentrations of Na, Ti, and Zr tend to decrease when garnets
become more refractory, but variations of Sr and Li are more complex. Compositions rich in light REE and relatively poor in
high field strength elements (HFSE) of the harzburgitic garnet inclusions in diamonds are generally consistent with metasomatism
by carbonatite melts. The trace element features observed from the garnet inclusions in Chinese diamonds may be caused by
carbonatite melt infiltration and partial melt extraction. Spatial and temporal gradients in melt/rock ratio and temperature
are the main reasons for the large variations of REE patterns and other trace element concentrations.
Received: 27 April 1999 / Accepted: 1 March 2000 相似文献
13.
Notable within-crystal variability of mineralogical and geochemical properties of single natural diamonds are commonly attributed to changing chemistry of parental fluids, sources of carbon and redox conditions of diamond precipitation. A distinct type of compositional heterogeneity (mixed-habit structure) is well-known to occur in diamonds as well as in many other minerals due to purely “structural” reasons that are unequal crystal chemistry of crystallographically different faces and selective absorption and fractionation of impurities between adjacent growth pyramids. Based on the combined cathodoluminescence, Fourier-transformed infrared spectroscopy and photoluminescence spectroscopy, study of nine diamond crystals with different growth histories and external morphology, but all showing mixed-habit patterns at different growth stages, we show that mixed-diamonds may grow in closed system conditions or with a slowly decreasing growth rate from a media with a much lower impurity content than previously thought. Intracrystal nitrogen distribution seems to be a function of growth rate even in the cases of unusual impurity partitioning between growth sectors. Generally poor with IR-active hydrogen at moderate nitrogen aggregation parameters, studied diamonds likely resemble the low hydrogen content from the growth medium that, for cubic diamonds, was typically suggested hydrogen-rich and a crucial factor for growth of cubic and mixed-habit diamonds. We also show that mixed-habit diamond growth may occur not only in peridotitic suite but also in an extended field of geochemical affinities from high-Ni to low-Ni or maybe even Ni-free environments, such as pyroxenitic or eclogitic. 相似文献
14.
15.
D. F. Wiggers de Vries M. R. Drury D. A. M. de Winter G. P. Bulanova D. G. Pearson G. R. Davies 《Contributions to Mineralogy and Petrology》2011,161(4):565-579
As a step towards resolving the genesis of inclusions in diamonds, a new technique is presented. This technique combines cathodoluminescence
(CL) and electron backscatter diffraction (EBSD) using a focused ion beam–scanning electron microscope (FIB–SEM) instrument
with the aim of determining, in detail, the three-dimensional diamond zonation adjacent to a diamond inclusion. EBSD reveals
that mineral inclusions in a single diamond have similar crystallographic orientations to the host, within ±0.4°. The chromite
inclusions record a systematic change in Mg# and Cr# from core to the rim of the diamond that corresponds with a ~80°C decrease
of their formation temperature as established by zinc thermometry. A chromite inclusion, positioned adjacent to a boundary
between two major diamond growth zones, is multi-faceted with preferred octahedral and cubic faces. The chromite is surrounded
by a volume of non-luminescent diamond (CL halo) that partially obscures any diamond growth structures. The CL halo has apparent
crystallographic morphology with symmetrically oriented pointed features. The CL halo is enriched in ~200 ppm Cr and ~80 ppm
Fe and is interpreted to have a secondary origin as it overprints a major primary diamond growth structure. The diamond zonation
adjacent to the chromite is complex and records both syngenetic and protogenetic features based on current inclusion entrapment
models. In this specific case, a syngenetic origin is favoured with the complex form of the inclusion and growth layers indicating
changes of growth rates at the diamond–chromite interface. Combined EBSD and 3D-CL imaging appears an extremely useful tool
in resolving the ongoing discussion about the timing of inclusion growth and the significance of diamond inclusion studies. 相似文献
16.
同步辐射白光形貌术具有射线强度大、准直性好、摄谱时间短、分辨率高等特点,是无损研究晶体缺陷的有效工具．采用该方法对产自山东蒙阴、辽宁瓦房店和湖南沅江3个矿区的31颗典型金刚石样品进行了研究．白光形貌像揭示,金刚石中普遍存在晶体结构畸变的特征,并且变形程度不等,部分严重变形晶体具有异常劳埃衍射式样;其衍射斑点的形态、衬度及条纹变化反映了金刚石晶体结构变形的程度和复杂性．晶格的完整性与金刚石的褐色强度无明显相关性．该类结构缺陷与金刚石的复杂形成过程和深部保存条件有关． 相似文献
17.
Forty-one diamonds sourced from the Juina-5 kimberlite pipe in Southern Brazil, which contain optically identifiable inclusions, have been studied using an integrated approach. The diamonds contain <20 ppm nitrogen (N) that is fully aggregated as B centres. Internal structures in several diamonds revealed using cathodoluminescence (CL) are unlike those normally observed in lithospheric samples. The majority of the diamonds are composed of isotopically light carbon, and the collection has a unimodal distribution heavily skewed towards δ13C ~ ?25 ‰. Individual diamonds can display large carbon isotope heterogeneity of up to ~15 ‰ and predominantly have isotopically lighter cores displaying blue CL, and heavier rims with green CL. The light carbon isotopic compositions are interpreted as evidence of diamond growth from abiotic organic carbon added to the oceanic crust during hydrothermal alteration. The bulk isotopic composition of the oceanic crust, carbonates plus organics, is equal to the composition of mantle carbon (?5 ‰), and we suggest that recycling/mixing of subducted material will replenish this reservoir over geological time. Several exposed, syngenetic inclusions have bulk compositions consistent with former eclogitic magnesium silicate perovskite, calcium silicate perovskite and NAL or CF phases that have re-equilibrated during their exhumation to the surface. There are multiple occurrences of majoritic garnet with pyroxene exsolution, coesite with and without kyanite exsolution, clinopyroxene, Fe or Fe-carbide and sulphide minerals alongside single occurrences of olivine and ferropericlase. As a group, the inclusions have eclogitic affinity and provide evidence for diamond formation at pressures extending to Earth’s deep transition zone and possibly the lower mantle. It is observed that the major element composition of inclusions and isotopic compositions of host Juina-5 diamonds are not correlated. The diamond and inclusion compositions are intimately related to subducted material and record a polybaric growth history across a depth interval stretching from the lower mantle to the base of the lithosphere. It is suggested that the interaction of slab-derived melts and mantle material combined with subsequent upward transport in channelised networks or a buoyant diapir explains the formation of Juina-5 diamonds. We conclude that these samples, despite originating at great mantle depths, do not provide direct information about the ambient mantle, instead, providing a snapshot of the Earth’s deep carbon cycle. 相似文献
18.
G. P. Bulanova W. L. Griffin C. G. Ryan O. Y. Shestakova S.-J. Barnes 《Contributions to Mineralogy and Petrology》1996,124(2):111-125
Sulfide inclusions in diamonds may provide the only pristine samples of mantle sulfides, and they carry important information
on the distribution and abundances of chalcophile elements in the deep lithosphere. Trace-element abundances were measured
by proton microprobe in >50 sulfide inclusions (SDI) from Yakutian diamonds; about half of these were measured in situ in polished plates of diamonds, providing information on the spatial distribution of compositional variations. Many of the
diamonds were identified as peridotitic or eclogitic from the nature of coexisting silicate or oxide inclusions. Known peridotitic
diamonds contain SDIs with Ni contents of 22–36%, consistent with equilibration between olivine, monosulfide solid solution
(MSS) and sulfide melt, whereas SDIs in eclogitic diamonds contain 0–12% Ni. A group of diamonds without silicate or oxide
inclusions has SDIs with 11–18% Ni, and may be derived from pyroxenitic parageneses. Eclogitic SDIs have lower Ni, Cu and
Te than peridotitic SDIs; the ranges of the two parageneses overlap for Se, As and Mo. The Mo and Se contents range up to
700 and 300 ppm, respectively; the highest levels are found in peridotitic diamonds. Among the in-situ SDIs, significant Zn and Pb levels are found in those connected by cracks to diamond surfaces, and these elements reflect
interaction with kimberlitic melt. Significant levels of Ru (30–1300 ppm) and Rh (10–170 ppm) are found in many peridotitic
SDIs; SDIs in one diamond with wustite and olivine inclusions and complex internal structures have high levels of other platinum-group
elements (PGEs) as well, and high chondrite-normalized Ir/Pd. Comparison with experimental data on element partitioning between
crystals of monosulfide solid solution (MSS) and sulfide melts suggests that most of the inclusions in both parageneses were
trapped as MSS, while some high-Cu SDIs with high Pd±Rh may represent fractionated sulfide melts. Spatial variations of SDI
composition within single diamonds are consistent with growth histories shown by cathodoluminescence images, in which several
stages of growth and resorption have occurred within magmatic environments that evolved during diamond formation.
Received: 5 July 1995 / Accepted: 21 February 1996 相似文献