本文選題：廣西大化 + 透閃石玉　； 參考：《中國地質(zhì)大學(xué)(北京)》2015年碩士論文

【摘要】：本文對廣西大化透閃石玉進(jìn)行寶石學(xué)、礦物學(xué)特征研究,推測其礦床成因,并從寶石學(xué)特征、成分、結(jié)構(gòu)和成因等方面與其它產(chǎn)地軟玉對比,分析各產(chǎn)地之間的差異,為玉石鑒定和開發(fā)利用提供指導(dǎo)作用。廣西大化透閃石玉顏色主要為青白色、灰綠色,表面有風(fēng)化現(xiàn)象。多數(shù)樣品呈微透明至不透明,光澤較弱,為蠟狀光澤至弱油脂光澤,內(nèi)部有白色、黑色斑點(diǎn)狀或脈狀雜質(zhì)。通過常規(guī)寶石學(xué)測試,廣西大化透閃石玉的密度范圍在2.90~2.97 g/cm3,平均為2.94 g/cm3;測試樣品的摩氏硬度范圍在5.32~6.06,平均為5.70;折射率范圍在1.60~1.62,略低于軟玉標(biāo)準(zhǔn)。偏光顯微鏡下薄片觀察,廣西大化透閃石玉結(jié)構(gòu)主要有:毛氈狀纖維變晶結(jié)構(gòu)、顯微纖維變晶結(jié)構(gòu)等;圍巖樣品為具輝綠結(jié)構(gòu)的輝綠巖和粒狀結(jié)構(gòu)的透閃石化白云巖。主要礦物為纖維狀、束狀的透閃石,次要礦物為粒狀的透輝石、方解石、綠泥石、石英,纖維狀的陽起石等。掃描電鏡觀察透閃石玉樣品表面微形貌特征,可見透閃石玉為顯微纖維交織結(jié)構(gòu)、定向顯微纖維結(jié)構(gòu)、顯微片狀結(jié)構(gòu)。通過傅里葉紅外光譜儀、X射線粉晶衍射測試,數(shù)據(jù)分析結(jié)果基本與標(biāo)準(zhǔn)透閃石數(shù)據(jù)接近,可知其主要化學(xué)成分為透閃石。通過電子探針對樣品的化學(xué)組成進(jìn)行測試,其化學(xué)組成主要為Ca O、Mg O、Si O2,還有Fe O、Mn O、K2O、Na2O、Al2O3、Ti O2等,結(jié)合背散射圖像觀察,樣品的礦物組成與偏光顯微鏡觀察結(jié)果基本一致,主要為透閃石、透輝石和綠泥石,還有磷灰石、榍石和鈣鐵榴石等。結(jié)合實(shí)驗(yàn)數(shù)據(jù),推測廣西大化透閃石玉礦床屬于巖漿熱液交代型礦床,其礦床成因是輝綠巖等基性侵入巖及巖漿攜帶的熱液,在一定的溫壓條件下,與白云質(zhì)灰?guī)r等碳酸鹽巖發(fā)生接觸交代和熱液交代作用。將廣西大化透閃石玉的寶石礦物學(xué)特征與其他產(chǎn)地軟玉進(jìn)行對比,發(fā)現(xiàn)其寶石學(xué)性質(zhì)、成分和結(jié)構(gòu)與其它產(chǎn)地軟玉基本一致。由于國標(biāo)修改了和田玉的命名,和田玉不再具有產(chǎn)地意義,廣西大化透閃石玉符合現(xiàn)行的和田玉標(biāo)準(zhǔn)。作為新發(fā)現(xiàn)的透閃石玉礦床,商業(yè)價(jià)值潛力巨大,還需要更深入的研究,為合理開發(fā)和利用提供理論支持和技術(shù)指導(dǎo)。
[Abstract]:This paper studies the characteristics of gemmology and mineralogy of Dahua tremolite jade in Guangxi, infer the origin of the deposit, and compare the characteristics, composition, structure and origin of the deposit with that of other producing areas in order to analyze the differences between the different areas. To provide guidance for the identification, development and utilization of jade. Guangxi Dahua tremolite jade color is mainly green, grey-green, surface weathering phenomenon. Most of the samples were slightly transparent to opaque with weak luster, waxy luster to weak oil luster, white, black spotted or veined impurity inside. The density range of Guangxi Dahua tremolite jade is 2.90 ~ 2.97 g / cm ~ (-3), the average is 2.94 g / cm ~ (3), the Mohlich hardness range is 5.32 ~ 6.06, the average value is 5.70, and the refractive index range is 1.60 ~ 1.62, which is slightly lower than the standard of nephrite. Under polarizing microscope, the structure of Guangxi Dahua tremolite jade is mainly composed of felt-like fiber metamorphic structure, micro-fiber metamorphic structure and so on, and the surrounding rock samples are diabase with pyrophyllite structure and tremolite dolomite with granular structure. The main minerals are fibrous, bunchy tremolites, secondary minerals are granular diopside, calcite, chlorite, quartz, fibrous actinolite, etc. The microstructure of tremolite jade was observed by scanning electron microscope. It can be seen that tremolite jade has interlaced microstructure, directional microfiber structure and microflake structure. By Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction measurements show that the results of data analysis are basically close to those of standard tremolites, and the main chemical composition is tremolite. The chemical composition of the sample was tested by electron probe. The chemical composition of the sample was mainly CaOMg-OOSiO2, and the chemical composition of the sample was mainly FeOOMn-OK2OK2O-Na _ 2O-Al _ 2O _ 3-Ti _ 2O _ 2. The mineral composition of the sample was basically consistent with that observed by polarizing microscope combined with backscatter images. Mainly tremolite, diopside and chlorite, as well as apatite, sphene and calcium iron garnet and so on. Based on the experimental data, it is inferred that the Dahua tremolite deposit in Guangxi belongs to magmatic hydrothermal metasomatic type. The origin of the deposit is diabase and other basic intrusive rocks and hydrothermal fluid carried by magma under certain temperature and pressure conditions. Contact metasomatism and hydrothermal metasomatism occur with carbonate rocks such as dolomitic limestone. The gemstone mineralogical characteristics of Guangxi Dahua tremolite jade are compared with those of other origin nephrite. It is found that the gemstone properties, composition and structure of Guangxi Dahua tremolite jade are basically the same as those of other origin nephrite. Because the national standard has modified the name of Hotan jade, Hetian jade no longer has the significance of producing area, Guangxi Dahua tremolite jade conforms to the current Hotan jade standard. As a newly discovered tremolite deposit, the commercial value of the deposit has great potential and needs more in-depth research to provide theoretical support and technical guidance for rational development and utilization.
【學(xué)位授予單位】：中國地質(zhì)大學(xué)(北京)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：P619.28

【共引文獻(xiàn)】

相關(guān)期刊論文 前10條

1 王鐸;徐澤彬;孫猛;曹姝e，

本文編號(hào)：1995247