Ⅰa型褐色金刚石结构缺陷的同步辐射白光形貌特征

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．     

辽宁天然金刚石晶体缺陷的X射线形貌研究

本文利用透射X射线衍射形貌术研究辽宁天然金刚石晶体缺陷的问题。实验结果表明,金刚石晶体中存在有位错、亚结构及包裹体等缺陷。从这些研究中可以找到辽宁天然金刚石成矿时的某些特点     

金刚石塑性变形的同步辐射X射线形貌研究及其意义

金刚石的塑性变形问题,近年来已经引起国内、外地质学家和矿物学家的极大兴趣和热烈讨论.并认为金刚石的塑性变形是金刚石呈褐色的主要原因,我们通过75颗不同成因,不同类型的彩色金刚石的同步辐射X射线单色光形貌和白色光形貌特征研究表明,不仅褐色金刚石有强烈的塑性变形,而且淡红色、红色、黄绿色和灰色金刚石都可见到有强烈的塑性变形[1].     

祖母绿和草莓红绿柱石的同步辐射X射线形貌研究

<正>目前,国内外对于矿物的同步辐射X射线形貌像研究,主要利用连续辐射即白光形貌作分析(蒋建华,2000;坦纳,1985;于万里等,2002),金刚石已经有人作了一些研究,有关单色光形貌研究方面少见,只有蒙宇飞等(2005)。草莓红绿柱石晶体化学的研究,作者已发表过多篇的文章     

化学气相沉淀法合成单晶金刚石膜实验探索

采用微波等离子体化学气相沉淀法合成了单晶金刚石膜,探索了化学气相沉淀法（CVD）单晶金刚石膜的生长机理。实验仪器采用石英管式微波等离子体化学气相沉积装置,种晶为3颗IaAB型天然金刚石原石,生长面近平行于（111）和（110）方向,生长温度为800℃,压力约为6kPa,时间约为8h。使用宝石显微镜和环境扫描电子显微镜观察分析了CVD单晶金刚石膜的生长表面形貌。结果表明,在生长面上可见明显的生长层,生长晶体无色透明,CVD单晶金刚石膜在生长面上横向外延生长,并形成定向的台阶状表面——“阶梯流”。在相同的条件下,（111）方向上生长的CVD单晶金刚石膜比（110）方向上的更有序。H2浓度的大小对CVD单晶金刚石膜的质量有影响。     

西藏罗布莎铬铁矿床中的金刚石包体X射线衍射研究

在西藏罗布莎蛇绿岩的豆荚状铬铁矿石及橄榄岩中找到了金刚石，少数金刚石存在有硅酸盐包体。本研究采用X射线衍射中的CCD（电子藕合）探测技术，测得了粒度仅为20μm左右的包体矿物的粉晶X衍射数据，数据表明该硅酸盐包体有两种，为滑石和蛇纹石，从而说明了西藏罗布莎产于蛇绿岩中的金刚石是天然金刚石，并非“人工合成物”。     

辽宁复县金刚石的阴极发光特征及其意义

阴极发光图像揭示了辽宁复县金刚石的内部结构具有３种类型;（１）简单的生长环带结构;（２）多期生长的复杂环带结构;（３）稀少的似玛瑙状结构,这些内部结构特征反映金刚石的不均一性及生长具多期、多阶段特点、该特点与金刚石所处的流体－熔体的不同阶段相对应。玛瑙状结构除多生长中心聚集形成复杂种晶形态所致外,局部不均匀熔蚀、混合的生长机制的变化的结晶条件三者综合作用亦是原因之一,阴有发光图像还反映了金刚石晶体     

重力均衡异常与湖南原生金刚石矿床预测

已有的研制表明,重力均衡异常既反映了地壳深处（软流层）的构造活动,又反映其活动的近期性。因此,在湖南原生金刚石矿床的预测时空域中,应注意沅水流域年青金刚石载体的勘查。     

菊花石形貌测量及生长机理探讨

对华南栖霞组中菊花石花瓣单晶及花体总貌（即矿物集合体形貌）中的各细节进行了测量与统计,确定了菊花石各中花瓣的结晶取向关系及花体总貌中的某些特征参数,探讨了菊花石的生长机理并用其解释菊花石的形貌特征及结晶环境。     

基于功率谱密度的评估岩石节理粗糙度新方法

为进一步提高结构面粗糙特征描述的精确性和可靠性,更全面地体现出细微形貌的影响,将轮廓线凹凸起伏分解为幅值、倾角和曲率3个特征,分别代表轮廓线的高度变化、角度变化和弯曲程度变化。以Barton建议的10条标准轮廓线为例,计算其幅度、角度和弯曲度的特征曲线,获得了三者的分布规律。利用可表征微细观形貌的功率谱密度函数研究了3种特征曲线的频谱特征,然后从功率谱密度对数曲线中提取了可以描述形貌特征的分形参数D_j（斜率相关）和粗糙度参数A_j（截距相关）,在此基础上研究了D_j和A_j与节理粗糙度系数（joint roughness coefficient,简称JRC）的关系。同时,将该指标推广到了三维形貌的表征形式,并计算了大理岩剪切面的三维粗糙度。结果表明：新指标评估精确度高,可反映结构面各向异性特征,能有效表征结构面粗糙特征,对研究结构面剪切力学性质有重要意义。     

不同类型彩色金刚石的谱学研究及其意义

对25颗不同类别的彩色金刚石进行了傅里叶显微红外光谱、紫外—可见—近红外吸收光谱、光致发光谱、拉曼光谱和X光荧光谱等谱学方法的研究。通过对近200张谱图的综合分析得到天然、合成、高温高压处理和人工辐射处理等彩色金刚石的特征谱,为金刚石类别的鉴定提供了标型,为研究彩色金刚石晶体缺陷引起的晶格畸变、晶格重组,以及色心的产生和消亡提供了新的证据。     

以碳酸盐为碳源生成金刚石的实验研究

本世纪五十年代初,在金属触媒物质的参与下,由石墨得到金刚石的成功,标志着人工合成超硬材料及高温高压技术两方面的巨大突破。三十年来的科学研究和生产实践推动着这一领域不断地向纵深发展,并提出了建立在不同理论基础上的金刚石生成方法,如爆破法、晶种法、气相生长法、常压高温法、薄膜推移法等等。     

Olivine with diamond-imposed morphology included in diamonds. Syngenesis or protogenesis?

The identification of syngenetic inclusions in diamond (i.e. inclusions of minerals that crystallized at the same time and by the same genesis as their host) has long been of paramount importance in diamond studies. However, the widespread assumption that many or most inclusions in diamonds are syngenetic is based on qualitative morphological criteria and few direct measurements. In order to provide statistically significant information on inclusion–host genetic relations for at least one kimberlite, we have determined the crystallographic orientations of 43 olivine inclusions with diamond-imposed morphology, a feature generally interpreted to indicate syngenesis, in 20 diamonds from the Udachnaya kimberlite (Siberia). Our unprecedented large data set indicates no overall preferred orientation of these olivines in diamond. However, multiple inclusions within a single diamond frequently exhibit similar orientations, implying that they were derived from original single monocrystals. Therefore, regardless of the possible chemical re-equilibration during diamond-forming processes, at least some of the olivines may have existed prior to the diamond (i.e. they are protogenetic). Our results imply that a diamond-imposed morphology alone cannot be considered as unequivocal proof of syngenicity of mineral inclusions in diamonds.     

Black material on mineral inclusions and in internal fracture planes in diamond

The black material observed on the surface of crystalline inclusions in diamond and also in adjacent internal fracture planes has been classified as a result of a preliminary examination of several hundred diamonds from Sierra Leone, Ghana, and South Africa (particularly the Premier Mine), as well as diamond slices of unknown origin, followed by a detailed examination of some 100 diamonds. X-ray, electron diffraction, and qualitative electron microprobe techniques were used in identifying this material as graphite, pyrrhotite and pentlandite. The possible origins of these minerals are discussed.     

Diamonds and Their Mineral Inclusions,and What They Tell Us: A Detailed “Pull-Apart” of a Diamondiferous Eclogite

For the first time, three-dimensional, high-resolution X-ray computed tomography (HRXCT) of an eclogite xenolith from Yakutia has successfully imaged diamonds and their textural relationships with coexisting minerals. Thirty (30) macrodiamonds (≥1 mm), with a total weight of just over 3 carats, for an ore grade of some 27,000 ct/ton, were found in a small (4 × 5 × 6 cm) eclogite, U51/3, from Udachnaya. Based upon 3-D imaging, the diamonds appear to be associated with zones of secondary alteration of clinopyroxene (Cpx) in the xenolith. The presence of diamonds with secondary minerals strongly suggests that the diamonds formed after the eclogite, in conjunction with meta-somatic input(s) of carbon-rich fluids. Metasomatic processes are also indicated by the non-systematic variations in Cpx inclusion chemistry in the several diamonds. The inclusions in the diamonds vary considerably in major- and trace-element chemistry within and between diamonds, and do not correspond to the minerals of the host eclogite, whose compositions are extremely homogeneous. Some Cpx inclusions possess +Eu anomalies, probably inherited from their crustal source rocks. The only consistent feature for the Cpx crystals in the inclusions is that they have higher K₂O than the Cpx grains in the host.

The δ¹³C compositions are relatively constant at ?5% both within and between diamonds, whereas δ¹⁵N values vary from ?2.8% to ?15.8%. Within a diamond, the total N varies considerably from 15 to 285 ppm in one diamond to 103 to 1250 ppm in another. Cathodoluminescent imaging reveals extremely contorted zonations and complex growth histories in the diamonds, indicating large variations in growth environments for each diamond.

This study directly bears on the concept of diamond inclusions as time capsules for investigating the mantle of the Earth. If diamonds and their inclusions can vary so much within this one small xenolith, the significance of their compositions is a serious question that must be addressed in all diamond-inclusion endeavors.     

HPHT合成钻石在首饰中的鉴别特征

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.     

Episodic diamond genesis at Jwaneng, Botswana, and implications for Kaapvaal craton evolution

Major element and Re–Os isotope analysis of single sulfide inclusions in diamonds from the 240 Ma Jwaneng kimberlite has revealed the presence of at least two generations of eclogitic diamonds at this locality, one Proterozoic (ca. 1.5 Ga) and the other late Archean (ca. 2.9 Ga). The former generation is considered to be the same as that of eclogitic garnet and clinopyroxene inclusion bearing diamonds from Jwaneng with a Sm–Nd isochron age of 1.54 Ga. The latter is coeval with the 2.89 Ga subduction-related generation of eclogitic sulfide inclusion bearing diamonds from Kimberley formed during amalgamation of the western and eastern Kaapvaal craton near the Colesberg magnetic lineament.

The Kimberley, Jwaneng, and Premier kimberlites are key localities for characterizing the relationship between episodic diamond genesis and Kaapvaal craton evolution. Kimberley has 3.2 Ga harzburgitic diamonds associated with creation of the western Kaapvaal cratonic nucleus, and 2.9 Ga eclogitic diamonds resulting from its accretion to the eastern Kaapvaal. Jwaneng has two main eclogitic diamond generations (2.9 and 1.5 Ga) reflecting both stabilization and subsequent modification of the craton. Premier has 1.9 Ga lherzolitic diamonds that postdate Bushveld–Molopo magmatism (but whose precursors have Archean Sm–Nd model ages), as well as 1.2 Ga eclogitic diamonds. Thus, Jwaneng provides the overlap between the dominantly Archean vs. Proterozoic diamond formation evident in the Kimberley and Premier diamond suites, respectively. In addition, the 1.5 Ga Jwaneng eclogitic diamond generation is represented by both sulfide and silicate inclusions, allowing for characterization of secular trends in diamond type and composition. Results for Jwaneng and Kimberley eclogitic sulfides indicate that Ni- and Os-rich end members are more common in Archean diamonds compared to Proterozoic diamonds. Similarly, published data for Kimberley and Premier peridotitic silicates show that Ca-rich (lherzolitic) end members are more likely to be found in Proterozoic diamonds than Archean diamonds. Thus, the available diamond distribution, composition, and age data support a multistage process to create, stabilize, and modify Archean craton keels on a billion-year time scale and global basis.     

金刚石分类、组成特征以及我国金刚石研究展望

金刚石由于其独特的物理化学性质,在经济生产与科学研究中均具有重要价值.金刚石形成于地球大于150 km的深度范围内,是人类可以获得的来自地球深部地幔乃至核幔边界的最直接的样品,因此可以为研究地球深部物质组成和物理化学条件提供重要的素材.金刚石由碳元素组成,还含有微量的杂质元素（如氮、硼、氢、氧等）,其中氮和硼元素对于划分金刚石的晶体结构类型发挥着重要的作用.根据金刚石的产出类型,金刚石可以划分为幔源型、超高压变质型、陨石相关型以及蛇绿岩型金刚石.全球约百分之一的幔源型金刚石含有包裹体,对这些包裹体的研究显示,金刚石主要来源于地球150~200 km深度的岩石圈地幔.这些含有包裹体的金刚石中,仅有1%的金刚石来自于地球深部的软流圈、地幔过渡带、下地幔、甚至核幔边界.我国的金刚石产出类型多样,但是,目前仅山东蒙阴、辽宁复县的金伯利岩矿床以及湖南沅水的砂矿具有经济价值.蛇绿岩型金刚石是近年来金刚石研究领域取得的重要进展,该类型金刚石分布在全球多个造山带不同时代、不同构造属性的蛇绿岩地幔橄榄岩和铬铁矿中,被认为是一种新的金刚石的产出类型.相对于其他国家和地区的金刚石的研究,我国的金刚石领域的研究程度相对较低,缺乏对金刚石结构、化学组成以及包裹体组成的系统研究,制约了对我国金刚石成因的认识,限制了我国的金刚石的找矿工作.因此,亟需结合先进的分析手段对我国的金刚石及其围岩做进一步的研究,以期揭示金刚石的形成过程,为金刚石的找矿提供理论基础.      

Nature of diamonds in Yakutian eclogites: views from eclogite tomography and mineral inclusions in diamonds

We have performed dissections of two diamondiferous eclogites (UX-1 and U33/1) from the Udachnaya kimberlite, Yakutia in order to understand the nature of diamond formation and the relationship between the diamonds, their mineral inclusions, and host eclogite minerals. Diamonds were carefully recovered from each xenolith, based upon high-resolution X-ray tomography images and three-dimensional models. The nature and physical properties of minerals, in direct contact with diamonds, were investigated at the time of diamond extraction. Polished sections of the eclogites were made, containing the mould areas of the diamonds, to further investigate the chemical compositions of the host minerals and the phases that were in contact with diamonds. Major- and minor-element compositions of silicate and sulfide mineral inclusions in diamonds show variations among each other, and from those in the host eclogites. Oxygen isotope compositions of one garnet and five clinopyroxene inclusions in diamonds from another Udachnaya eclogite (U51) span the entire range recorded for eclogite xenoliths from Udachnaya. In addition, the reported compositions of almost all clinopyroxene inclusions in U51 diamonds exhibit positive Eu anomaly. This feature, together with the oxygen isotopic characteristics, is consistent with the well-established hypothesis of subduction origin for Udachnaya eclogite xenoliths. It is intuitive to expect that all eclogite xenoliths in a particular kimberlite should have common heritage, at least with respect to their included diamonds. However, the variation in the composition of multiple inclusions within diamonds, and among diamonds, from the same eclogite indicates the involvement of complex processes in diamond genesis, at least in the eclogite xenoliths from Yakutia that we have studied.     

Comparison of enigmatic diamonds from the Tolbachik arc volcano (Kamchatka) and Tibetan ophiolites: Assessing the role of contamination by synthetic materials

The enigmatic appearance of cuboctahedral diamonds in ophiolitic and arc volcanic rocks with morphology and infrared characteristics similar to synthetic diamonds that were grown from metal solvent requires a critical reappraisal. We have studied 15 diamond crystals and fragments from Tolbachik volcano lava flows, using Fourier transform infrared spectrometry (FTIR), transmission electron microscopy (TEM), synchrotron X-ray fluorescence (SRXRF) and laser ablation inductively coupled plasma mass-spectrometry (LA-ICP-MS). FTIR spectra of Tolbachik diamonds correspond to typical type Ib patterns of synthetic diamonds. In TEM films prepared using focused ion beam technique, we find Mn-Ni and Mn-Si inclusions in Tolbachik diamonds. SRXRF spectra indicate the presence of Fe-Ni and Fe-Ni-Mn inclusions with Cr, Ti, Cu, and Zn impurities. LA-ICP-MS data show variable but significantly elevated concentrations of Mn, Fe, Ni, and Cu reaching up to 70 ppm. These transition metal concentration levels are comparable with those determined by LA-ICP-MS for similar diamonds from Tibetan ophiolites. Mn-Ni (+Fe) solvent was widely used to produce industrial synthetic diamonds in the former USSR and Russia with very similar proportions of these metals. Hence, it appears highly probable that the cuboctahedral diamonds recovered from Kamchatka arc volcanic rocks represent contamination and are likely derived from drilling tools or other hard instruments. Kinetic data on diamond dissolution in basaltic magma or in fluid phase demonstrate that diamond does not form under the pressures and temperature conditions prevalent within the magmatic system beneath the modern-day Klyuchevskoy group of arc volcanoes. We also considered reference data for inclusions in ophiolitic diamonds and compared them with the composition of solvent used in industrial diamond synthesis in China. The similar inclusion chemistry close to Ni₇₀Mn₂₅Co₅ for ophiolitic and synthetic Chinese diamonds scrutinized here suggests that most diamonds recovered from Tibetan and other ophiolites are not natural but instead have a synthetic origin. In order to mitigate further dubious reports of diamonds from unconventional tectonic settings and source rocks, we propose a set of discrimination criteria to better distinguish natural cuboctahedral diamonds from those produced synthetically in industrial environments and found as contaminants in mantle- and crust-derived rocks.