江西绿柱石矿床的基本特征与绿柱石类宝石的找矿方向

本文在总结江西绿柱石矿床的区域分布、产出类型、矿化组合、成矿控矿作用等基本特征的基础上，阐明了江西所产绿柱石的矿物学特点、成矿条件，并对寻找宝石级绿柱石有前景的地区进行了预测，圈出了Ａ、Ｂ、Ｃ三类预测区１０处，提出了对近期宝石地质普查和开发工作的建议。     

四川虎牙雪宝顶W-Sn-Be矿床矿物学标型特征及流体对矿物形态的影响

四川虎牙乡雪宝顶钨锡铍矿床产出宝石级绿柱石、白钨矿、锡石、电气石等矿物且晶形完好.共生矿物有长石、方铅矿、石英、方解石、云母等.绿柱石、白钨矿和锡石色彩绚丽, 其成分较为复杂, 类质同象现象普遍, 晶体形貌具有标型意义.对该区代表性矿物绿柱石、白钨矿、锡石等进行了成分研究、形貌描述及矿物共生组合特点分析, 从矿物标型特征、围岩蚀变类型确定了矿床属于高温热液云英岩脉型矿床, 在此基础上重点探讨了板状绿柱石成因.      

绿柱石的成因与特征的研究

绿柱石是提炼稀有金属铍的重要矿石矿物,也是重要的宝石矿物。文章从绿柱石的矿床特点、包裹体和谱学特征、绿柱石的优化处理及人工合成等方面,对国内近年来在绿柱石研究方面的进展进行了综述,并对绿柱石的研究方向提出了一些建议。     

四川平武板状绿柱石矿物学特征及板状成因

在综合该区绿柱石产出背景的基础上,从围岩蚀变、矿物共生组合、矿物标型形态和绿柱石测温测压等方面确定平武绿柱石矿床是气成高温浅成石英脉型矿床。文中对绿柱石矿物进行了湿法化学分析、X射线粉晶衍射分析、微形貌分析,研究了该区绿柱石的形态、物性、化学成分及类质同象特征,确定该区绿柱石为板状晶形的含铯钠锂绿柱石,碱金属平均质量分数为2.412%(Li2O+Na2O+K2O+ Rb2O+Cs2O)。板状含碱绿柱石一般发育在伟晶岩中,气成高温热液矿床中产出板状含碱绿柱石极为罕见。在以上工作基础上,从绿柱石形成的内因和外因两方面探讨了绿柱石的板状成因。     

绿柱石——一种主要的宝石矿物

宝石矿物是当前矿物学重点研究发展方向之一,是我国急需的矿种,珍贵的工艺品原料,绿柱石则是主要的宝石矿物。本文详细介绍了:绿柱石宝石的九个变种,尤其阐述了变种祖母绿——五大珍贵宝石之一的形态和物理化学特征;它们的鉴别特征;与相似宝石的区别;人工合成绿柱石与天然绿石的区别;绿柱石宝石的人工处理——改变或改善原来宝石的颜色或外观,提高其价值;有关各国绿柱石宝石的收藏和生产情况。     

吉林白山地区玄武岩中宝石矿床成矿特征

白山市矿产资源丰富,宝石矿床种类繁多,具有十分重要的研究价值及经济意义.本文仅对碱性玄武岩中宝石矿床产出的构造背景及相关联的蓝宝石、橄榄石矿床的形成条件、特征及成矿规律进行探讨.     

产在太古代绿岩带科马提岩内的绿柱石矿床

以往认为绿柱石多与酸性岩、伟晶岩有关,但近10年在巴西等地的科马提岩内发现了绿柱石。巴西Santa Terezinha矿床在巴西的中西部,是1981年发现的。绿柱石可做宝石,品位达     

四川平武钨锡铍矿床成矿流体特征

四川平武新近发现多处规模较大的产于晶洞中的绿柱石、锡石和白钨矿宝石矿。本文对矿石矿物绿柱石、锡石和白钨矿中的流体包裹体进行了分析，直接获取了成矿期的流体信息，由于绿柱石、锡石的结晶均较早，故更为接近原始成矿流体的性质。平武钨锡铍宝石矿中流体包裹体有气液两相包裹体、CO2三相包裹体和含子矿物包裹体三种类型。包裹体完全均一温度最佳取值区间为260～300℃，盐度范围为0．53％～8．73％NaCleq，压力估算小于10．5MPa，矿床类型属于浅成中低温热液型。绿柱石中含子矿物包裹体和CO2三相包裹体共存，二者均一温度平均值较为相近，显示了不混溶流体包裹体的特征。绿柱石包裹体的完全均一温度和盐度平均值均高于白钨矿和锡石，绿柱石和白钨矿包裹体液相成分中F^-、Cl^-离子含量高于锡石。绿柱石、白钨矿和锡石三种矿物沉淀的先后顺序为：绿柱石→锡石→白钨矿。     

绿柱石中包裹体研究进展

从包裹体性质、类型、成分特征等方面详细介绍了近年来国内外绿柱石中包裹体研究在绿柱石的成因类型、形成条件及绿柱石宝石的产地的判别、绿柱石宝石的鉴别等方面的进展 ;同时也介绍了包裹体研究中某些测试技术的进展 ,并对绿柱石中包裹体研究提出了一些建议。     

新疆可可托海绿柱石猫眼矿物学特征及其开发探讨

在绿柱石的各个品种当中，绿柱石猫眼是比较独特的一个品种，经济价值较高。其内部因含有大量的定向排列的气液包体，所以在定向切割的弧面宝石中会出现猫眼效应。新疆阿尔泰可可托海地区产出大量的淡黄色、淡绿色、淡蓝色绿柱石猫眼。通过化学全分析、显微硬度仪、X光粉晶衍射、红外光谱、拉曼光谱对该地绿柱石猫眼的物理性质、化学成分、物质的结构、绿柱石分子中的结构水、内部包体的赋存状态、气液包体的化学成分进行了详细的研究和分析。同时计算出了晶体化学式、晶胞参数。为该地区绿柱石猫眼的研究和开发提供了较为系统和详细的资料。通过对其内部结构的认识，进行了改色和优化试验，获得了该绿柱石的宝石改善的新品种。     

四川平武绿柱石结晶学特征研究及发展前景

产于四川平武的绿柱石颜色呈现浅绿色至无色，透明至半透明，形状为独特的板状，是国内绿柱石呈现板柱晶形的唯一实例，其共生组合已经作为观赏石开发，采用电子探针，X射线分析等多种方法对平武绿柱石进行了结晶学的研究，并分析了其应用前景。     

MPV-3显微光度计在宝石学中的应用

简述ＭＰＶ－３显微光度计的特点,阐述了有色宝石颜色评价的理论基础和方法,以四川平武无色绿柱石,山东昌乐蓝宝石的颜色评价和改色实验效果评价以及不同成因的天然红工 光性研究为例,论述了ＭＰＶ３显微光度计在宝石颜色评价、改色效果判定、红宝石定名和品种鉴别等方面的应用。     

EPR investigation of NO2 and CO2 − and other radicals in beryl

A number of different impurities are located in the open channels of natural beryl crystals. The rare Maxixe beryl contains an unusual amount of NO₂. The isoelectronic CO₂ ⁻ radical is found in the irradiated Maxixe-type beryl. The NO₂ radicals are distributed in the Be–Al plane of the crystal, with the nitrogen atom close to the oxygens of the beryl cavity wall. These oxygens repel the negative CO₂ ⁻ radical, which is located at the center of the beryl cavity and rotates around its O–O axis, which is parallel to the crystal c-axis. When there is a nearby alkali ion at the center of the beryl channel, it reorients the CO₂ ⁻ radical so that its bisector is parallel to the c-axis and points toward the positive ion. Different signals are analyzed for Li⁺, Na⁺, and another counter-ion, which probably is Cs⁺. The related NO₃ and CO₃ ⁻ radicals are the color centers in the investigated deep blue beryls. The slow decay of the color, which makes these beryls useless as gem stones, is related to the decay of the hydrogen atoms which are present in these crystals. Evidence is given that NO₃ is created in Maxixe beryl by a natural process, while CO₃ ⁻ in Maxixe-type beryl has been created by irradiation. The temperature dependence of the EPR signals of these two radicals was investigated, but a definitive proof that they rotate at the center of the beryl cavity could not be given. EPR signals from some other radicals in beryl have been observed and described.     

Lithological and Structural Controls on the Genesis of Emerald Occurrences and their Exploration Implications in and around Gurabanda Area,Singhbhum Crustal Province,Eastern India

Emerald, the green gem variety of beryl (Be₃Al₂Si₆O₁₈), is the third most valuable gemstone after diamond and ruby. The green colour appearance of the crystal is due to trace of Cr³⁺ and V³⁺, which replaces Al³⁺ ions in the crystal lattice of beryl. The hue of green colour of emerald depends on the quantity of Cr³⁺ and V³⁺ present in the crystal. Be is incorporated along with Cr and/or V during the process of crystallization. Since Be is relatively rare in the upper continental crust, therefore specific geological and geochemical parameters are required for Be to be incorporated in the crystal lattice of emerald.The present work was carried out to understand the lithological and structural control of emerald occurrences in and around Gurabanda area within the Singhbhum shear zone (SSZ) of Singhbhum crustal province, eastern India. The biotite and serpentine schist belong to the Paleoproterozoic Dhanjori Group and constitute the major lithology of the area. Pegmatite and biotite schist contains a variety of gem minerals in abundance in the area and the gem quality emerald occur at the contact zone of quartz vein and mica-schist. Lithology and structure are the main controlling factors of gem-mineralization in the study area. The study indicates that regional metamorphism and deformation processes along the shear zone played a significant role in the formation of emerald deposits. It is inferred that Singhbhum shear zone facilitated a favourable condition, where the Be bearing pegmatites interacted with Cr bearing mica schist or ultramafic rocks to produce emerald crystal.     

Source rocks of gem minerals

Field and laboratory studies on the geology and mineralogy of gem sediments and associated rocks reveal that gem minerals occur both in garnetiferous gneisses and granulites. It has been observed that PT conditions characteristic of granulite facies had favoured the formation of gem minerals such as topaz, corundum, beryl, spinel, tourmaline and zircon.

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Resume Les travaux sur le terrain ainsi qu'au laboratoire portant sur les sédiments et les roches associes aux pierres precieuses montrent que les minéraux précieux se trouvent dans les gneiss à grenat et les granulites. Il a été observé que les conditions de pression et de température qui caractérisent le faciès des granulites ont favorise la formation des minéraux precieux tels que des topazes, corindons, béryls, spinelles, tourmalines et zircons.

     

The geochemistry of beryllium and fluorine in the gem fields of Sri Lanka

A study of the abundance of Be in the gem sediments of Sri Lanka shows that Be is found in the range of 1–13 ppm. Be shows an irregular distribution among sediments. It occurs in the silicate form and due to the proximity to the beryllium bearing rocks, namely granites and pegmatites of the Highland and Southwest Groups of Sri Lanka, very little decomposition of the Be-bearing minerals had taken place. This is further aided by the high resistance to weathering of the beryllium minerals, particularly beryl and chrysoberyl.The beryllian granites and pegmatites of the Precambrian of Sri Lanka are presumed to have been formed due to the magmatic activity associated and related to charnockitic rocks abundant in the main gem bearing areas of Sri Lanka.Fluorine is found in the range of 400–2,000 ppm and the F/Be ratios for all the areas studied show a range of 54–441. The analysis of the averages of these ratios do not show any particular anomaly in any of the areas studied. The narrow ranges of the F/Be ratios indicate the similar conditions under which weathering and geochemical transportation had taken place in the gem fields of Sri Lanka.     

Gemstone Mineralization in the Palghat-Cauvery Shear Zone System (Karur-Kangayam Belt), Southern India

We summarize here the occurrence of a number of semiprecious stones within a major gemstone belt in the Palghat-Cauvery shear zone system close to the northern margin of the Madurai Granulite Block, southern India. The gem mineralization in this belt includes different varieties of corundum (star ruby, sapphire), cordierite (iolite), feldspar (moonstones and sunstone of various hues), beryl (emerald, aquamarine), chrysoberyl (alexandrite), kornerupine, topaz, spinel, crystal quartz and amethyst, among others. Gem mineralisation has not been directly dated, but is associated with pegmatites that crosscut rocks metamorphosed in late Neoproterozoic/Early Cambrian times. Similar aged gem mineralization occurs south of the Achankovil Shear Zone in southern India, as well as in Sri Lanka and Madagascar and strengthen the view of a broad late Neoproterozoic-early Cambrian gemstone province in central Gondwana. The ruby mineralization within this belt can be correlated with similar occurrences in eastern Madagascar, supporting a correlation between the Malagasy Betsimisaraka suture zone and the Palghat-Cauvery shear zone system in southern India.     

Types and genetic mechanism of chrysoberyl depositsSCIEI北大核心CSCD

金绿宝石作为一种铍矿物,不仅能用于高新科技、军事、医疗等领域,也是一种珍贵的宝石。自十八世纪被发现以来,金绿宝石成因和矿床特征被广泛地关注与研究。本文梳理与归纳了金绿宝石矿物学特征、矿床类型与分布,并给出新的矿床划分方案;总结了金绿宝石矿床的形成机制和影响因素等方面研究进展及科学问题。金绿宝石矿床按照成因可分为四个大类,即熔体结晶类、变质成因类、交代成因类和风化成因类;而根据赋存岩石,可将金绿宝石矿床进一步划分为六种亚型,分别是花岗岩-伟晶岩型、变质伟晶岩型、蛇纹岩型、云母岩型、条纹岩型和砂矿型。金绿宝石可在高温的高分异花岗岩岩浆中直接结晶形成,主要与石英、长石、白云母、绿柱石等共生,也可见锌尖晶石、夕线石和红柱石;在高级变质条件下金绿宝石由绿柱石分解得到,在变质伟晶岩型中金绿宝石与长石和石英共生,而在蛇纹岩型中金绿宝石与硅铍石共生;由远端交代作用控制形成的条纹岩型金绿宝石常与萤石、硅铍石和塔菲石共生,而由近端交代作用控制形成的云母型金绿宝石则与金云母、绿柱石和硅铍石共生。金绿宝石矿床仍存在很多有待解决与深入探讨的科学问题：金绿宝石形成的温压范围比较大,可能存在不同晶体相;针对花岗岩-...