蓝色刚玉的致色改色理论分析

蓝色刚玉的致色改色理论分析常晓涛郑辙郑海飞（北京大学地质学系，北京１００８７１）关键词蓝宝石致色机理改色实验本文立足于原有蓝宝石的致色改色理论，通过实验及计算，对蓝宝石改色致色进行了基础性的理论研究，提出了杂质离子缺陷致色新认识，并以这一认识为原理，...     

山东省星光蓝宝石研究

山东昌乐是蓝宝石的主要产地之一.本文介绍了山东星光蓝宝石的特点,阐述了蓝宝石呈现星光与呈现光斑的机理,列举了使蓝宝石产生星光的针状包体的种类,论述了山东星光蓝宝石的性质特征、新发现致色离子类别、发光性、黄色变色蓝宝石及引起蓝宝石变色的元素以及星光蓝宝石分类、分级、评价原则.     

蓝宝石热处理的现状及前景

本文根据蓝宝石的致色机理,总结了蓝宝石热处理的模式及影响因素,给出了现行蓝宝石热处理的实例,结合国内经济发展状况对蓝宝石热处理的发展前景作了展望,并根据相关学科的发展提出了一些建议及设想。     

玄武岩型蓝宝石的颜色及找矿方向

目前市场上所销售的蓝宝石,有很大一部分产自以第三纪碱性玄武岩为母岩的次生矿床中.著名的产出国有澳大利亚、泰国、柬埔寨、中国,在老挝和越南也有这种类型的蓝宝石矿床.产自第三纪碱性玄武岩中的蓝宝石,不管属原生矿,还是次生矿,宝石矿物的共同特点是块度较大,颜色较浓,但是在反射光下,一般颜色较深,特别是块度大者几乎见不到蓝宝石色,暗黑色的外表,把美丽的天鹅绒蓝宝石色深深地     

蓝宝石主要致色元素与其颜色关系的实验研究

蓝宝石的颜色与主要致色元素的含量及其比值以及形成时的氧逸度有密切关系。本实验选用不同色调的蓝宝石,采用定量控制环境氧逸度的热处理方法,控制蓝宝石中主要致色离子的价态和比例。通过实验研究,获得（１）蓝宝石的颜色、透明度与氧逸度之间的关系曲线;（２）山东昌乐蓝宝石颜色与Ｆｅ、Ｔｉ含量及其比值之间关系曲线。Ｃｒ、Ｎｉ、Ｍｎ等多种杂质元素含量高会导致蓝宝石透明度降低,灰色调显著;（３）发现山东昌乐蓝宝石中存在α－Ｆｅ,它是蓝宝石颜色深,透明度差的重要原因之一。     

福建明溪蓝宝石矿物学特征及致色机理探讨

利用颜色测量、顺磁共振谱、红外光谱和热谱等方法研究明溪蓝宝石的矿物学特征和结构特性，明溪蓝宝石色深，蓝中带黄，二色性强，分析表明Fe主要以Fe^3 形式存在，Fe^3 的d-d电子跃迁和Fe^2 -Ti^4 、O-Fe境塌菏转移是明溪蓝宝石致色的主要因素；H含量对蓝色的形成有重要作用。     

山东蓝宝石的主要致色因素

山东蓝宝石颜色深暗,与其主要致色元素有着直接关系.对其化学成分进行分析认为:Cr2O3是红色、橙黄色、黄色的主要致色因素.而w(TiO2)低,w(TFeO)高,尤其是Fe3 大于全铁的90%,TFeO/TiO2比值大是山东蓝宝石颜色深暗的主要原因.对其紫外-可见光-近红外吸收光谱进行分析,进一步得出Cr3 离子的d-d电子跃迁、成对Fe3 离子、单Fe3 离子的d-d电子跃迁、Fe2 -Ti4 之间的电荷转移、Fe2 Fe3 之间的电荷转移等是山东蓝宝石致色的本质.代表绝大多数山东蓝宝石颜色的深蓝色蓝宝石,缺失紫外-可见光-近红外吸收光谱的575～711nm吸收带,即缺少Fe2 -Ti4 之间的电荷转移.因此,针对性地选择w(TiO2)高的蓝宝石进行改善,或是设法加入TiO2、减少Fe3 含量、在还原条件下改变其TFeO/TiO2的比值,应是目前山东蓝宝石改色的关键.     

福建明溪蓝宝石的谱学特征及颜色成因

采用颜色测量、紫外-可见光谱、红外光谱等方法对福建明溪蓝宝石进行的研究表明,明溪蓝宝石颜色蓝中带黄,二色性强。紫外-可见吸收光谱中377,388和451nm吸收带较强。这些吸收带是Fe3 的d－d和Fe3 —Fe3 ,交换相合离子间的电子跃迁引起的。810nm带存在于各色蓝宝石中,强度变化较大,有时伴随有510nm吸收带。它是由Fe2 —Fe3 电荷转移形成的。570nm吸收带只出现在蓝色或绿色的蓝宝石中。结合蓝宝石红外33loom－‘吸收带与宝石颜色之间的关系,笔者将570nm吸收带归属于H、Fe、Ti构成的致色缺陷团。这一研究结果对蓝宝石呈色机理的进一步研究和宝石的合成等具有重要意义。     

蓝宝石研究述评

从矿产资源、致色机理和改色工艺、包裹体及其影响等方面,对近15年来我国蓝宝石研究有代表性的主要成果进行了简要述评。对拓展蓝宝石资源的找矿提出了一些建议。     

福建明溪蓝宝石呈色机理研究

明溪蓝宝石呈色是铁，钛，铬等杂质过渡金属离子电子跃迁和电荷转移等因素共同作用的结果，但蓝色的深浅与铁的含量不呈简单的正相关关系，而更多地与铁，钛间含量的配比相关，Al2O3中OH的振动应成为人们关注的蓝宝石呈色影响因素之一。     

马达加斯加蓝色蓝宝石的颜色特征

为了了解马达加斯加蓝色蓝宝石的颜色特征,采用GemDialogue颜色系统对其进行了描述与分级。对比世界上主要产地（澳大利亚、斯里兰卡、柬埔塞、缅甸）蓝宝石的颜色特征发现,马达加斯加蓝色蓝宝石样品的黑色罩过高,使得其最终的颜色等级大多在1～4范围内,属于“商业级”。为了进一步确定马达加斯加蓝色蓝宝石样品的颜色特征及其与全Fe,Ti质量分数的关系,采用紫外一可见光分光光度计和电子探针测试了样品。结果显示,随着全Fe与Ti质量分数的增加,样品的蓝色加深;当蓝宝石样品中全Fe的质量分数为0．02％～0．75％、Ti的质量分数为0．006%～O．040％且其全Fe与Ti质量分数比值为10～30时,蓝宝石样品的颜色为纯正蓝色;当超出此范围时,蓝宝石样品通常含有绿色或紫色色调。     

Weathering impact on the colour of building stones of the ‘Gateway of India’ monument

To understand the effect of monsoon and marine environment on the colour of building stones of the ‘Gateway of India’ monument, 133 samples from different areas were assessed. Colour changes were evaluated using Microflash 200d colour spectrophotometer over a period of 1 year. The alteration in the stones effecting the colour change was studied by petrographic thin section, which shows that the colour change is associated with weathering of the feldspars.     

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。     

铀的光度分析进展

本文评述了铀光度测定法,包括各类显色剂应用及二元、多元光度体系性质及应用范围。     

Effect of heat treatment on tourmaline from Brazil

The crystal-chemical behaviour of tourmaline from Araçuaí, Minas Gerais state, Brazil, when subjected to heating in air atmosphere has been studied by several techniques, including EMPA, UV–Vis, TGA, and Mössbauer spectroscopy. The tourmaline samples are typically intermediate members of the elbaite-schorl series. The origin of colour and of its change after treatment has been discussed in terms of local disorder, presence of metal transition elements, oxidation of ferrous iron at the octahedral site, and simultaneous trap of the excess electron. These findings may be used to enhance the colour in tourmaline crystals or generate wanted colour changes.     

Mineralogical and colour changes of quartz sandstones by heat

Seven German and three Hungarian monumental sandstones have been tested in laboratory conditions to analyse the effect of heat. The studied quartz sandstones have a wide-range of cements and grain-sizes including silica-, carbonate-, clay- and ferrous mineral—cemented varieties of fine-, medium- to coarse-grained types. Cylindrical specimens were heated up to 150, 300, 450, 600, 750 and 900°C in an oven. The mineralogical and textural changes were recorded and compared by using microscopy, XRD, DTA-DTG and SEM. Colours and colour differences (a*, b*, L* values) were also measured and evaluated. Colour changes are related to mineral transformations. The most intense colour change is caused by the oxidation of iron-bearing minerals to hematite that takes place up to 900°C. When temperature increases the green glauconite becomes brownish while the chlorite changes to yellowish at first. The colour of burnt sandstone is not a direct indicator of burning temperature, since there are sandstones in which the burnt specimens are lighter and less reddish than the natural ones. Porosity increase is related to micro-cracking at grain boundaries (above 600°C) and within the grains (at and above 750°C) and mineral transformations. The clay mineral structure collapses at different temperatures (kaolinite up to 600°C, chlorite above 600°C) and leads to a slight increase in porosity. The most drastic change is observed in calcite cemented sandstones where the carbonate structure collapses at 750°C and CaO appears at 900°C. Subsequently it is transformed to portlandite due to absorption of water vapour from the air. This leads to the disintegration of sandstone at room temperature a few days after the heat shock.Special issue: Stone decay hazards     

山东蓝宝石的包裹体研究

运用激光拉曼光谱、电子探针、包裹体测温等方法,对山东蓝宝石中的包裹体进行分析和测试。发现山东蓝宝石中包裹体数量巨大,裂隙、色带、针状包裹体以及多相包裹体是其主要的特征。其中主要的固体包裹体有锆石、刚玉、黑云母、尖晶石等,而多相包裹体的成分主要为H2O、CO2及玻璃相。电子探针结果显示,Fe的含量对于蓝宝石的颜色及色带的发育有制约作用。     

Mantle-derived heat recorded by conodont colour alteration in the Carboniferous of the Isle of Man

A range of colour alteration index (CAI) values between 3.0 and 6.0 is recorded for conodont elements recovered from the Arundian to Brigantian (Dinantian, Lower Carboniferous) sequence around Castletown, Isle of Man. Mantle-derived heat, channelled through the Caledonian South Barrule pluton, is proposed as the major cause of these elevated values. A lower CAI of 2.5 is obtained from elements recovered from a borehole sunk into the concealed Namurian (Upper Carboniferous) deposits near Shellag Point; the Glen Mona pluton acted as the medium for mantle-derived heat in this instance. The CAI values which may have been established during a late Dinantian volcanic episode around Castletown were overprinted by the greater effects of heat emanating from the South Barrule pluton. The record of CAI 6.0 for a sample taken from the immediate vicinity of a dyke indicates a high level of very localized CAI elevation in the early Tertiary.     

新疆某地红宝石和蓝宝石矿物学研究

本文系统地研究了新疆某地红宝石和蓝宝石矿床,查明该矿床中红宝石和蓝宝石的粒度、形态、双晶、裂纹,包裹体形态和成分,硬度、密度、多色性、吸收性、Ne和No值,晶胞参数及化学成分等特征,从而为该类矿床的开发利用提供了重要信息。同时,根据这些宝石的物理性质和化学成分上的区别,进一步探讨了呈色机理。     

山东昌乐蓝宝石砂矿中磁铁矿的宝石矿物学特征研究

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。