卢龙红刚玉的颜色成因及优化条件的研究

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1、摘要本文对位于秦皂岛市卢龙县的红刚玉矿床进行了实地考察，采集了红刚玉和围岩样品，利用偏光显微镜、X射线衍射仪、X射线荧光光谱仪、紫外．可见光分光光度计、高温电阻炉等仪器设备，对其地质环境、颜色成因进行了分析，并用热处理的方法对刚玉进行了优化，研究了热处理的工艺条件及热处理对刚玉颜色、透明度及宝石学性质的影响。研究结果表明，秦皂岛卢龙红刚玉形成于太古代富铝片麻岩中。刚玉形成于两个世代，第一世代的刚玉是在区域变质作用中形成的，颗粒比较细小。第二世代的刚玉形成于混合岩化阶段，刚玉晶体颗粒粗大，自形程度比较高。卢龙产出的红刚玉颜色品级较低，杂色调较重。刚玉中C，的存在使刚玉表现出红色调，随

2、刚玉中Cr含量的减少，红色调减弱。由Fe2+．Fe3+、Fe2+．Ti4+之间的电荷转使刚玉出现蓝色调，严重影响了红刚玉的颜色。部分刚玉宝石中含有微量Ti3+，使宝石出现紫色调。ve3+的存在导致刚玉出现黄绿色调。对刚玉的优化采用高温下在空气中热处理的方法。深红-红色刚玉最佳热处理温度为1200℃，颜色较浅的灰色刚玉采用较高的热处理温度时效果较好。热处理过程采用较慢的升温速率效果较好。热处理后刚玉杂色调明显减弱，但透明度较差。其宝石学性质总体变化不大。关键词宝石；刚玉；致色元素；优化；热处理燕山大学T=学硕十学协论文AbstractInthethesistheredcorundum

3、swhichareexplodtatedfromLulongQinhuangdaoarestudied．Firstly,thedespositoftheredcorundumisreconnoitred，samplesofthecorundumsandthewallrocksalecollected．SecondlBthegeologicenvironmentofthecorundumandtheprincipleofcolourarestudied．Thirdly,weameliorateditscolourwiththebeattreatmentmethodandthenstu

4、dieditschangenessofcolour,transparencyandthegemologicalcharactersbeforeandaftertheheattreatment．Themaininstrumentsandtbeequipmentsusedintheexperimentarepolarizedmicrosope，XRF,XRD，ultraviolet-visiblelightspectrophotometerandhi曲temperaturefinanceandSOon．nIeresultsrevealthattheredcorunduminLulong

5、Qinhuangdaoisrootedinaluminum-bearinggneiss．Thecorundumformedintwogenerations．Corundumsformedinthefirstgenerationaresmallandxenomorphic．11lcfashionofgeologicactionisareametamorphose．Thegeologicactiontoformthecorundumsinthesecondgenerationiscommixlithification．111ecorundumsarelargerandmoreinerr

6、atic．n圮colouroftheredcorundumexploitatedinLulongislow-endandmotley．Thecr3+makesthecorundumred．wimtllereduceoftbecr3+．theintensityoftheredhuebecomeweaken．111etransferofelectonbettenFe2+．Fe3+andFe2+．Ti4+isthecausationwhichbringsthebluehueintothecorundum．Appearanceofthebluehuenlakesthecolourofred

7、corundummotley．AlittleamountofTi”execitedinthecorundumleadtopurplehue．n站courseofyellowandgreenhueistheeontationofFe3+．Inordertoamelioratethecolouroftheredcorundum，weusethemothodofbeattreatment．nlctemperaturewhichisappropriatcd、Ⅳimthebea