本文選題：寶石學(xué)特征 + 硬玉　； 參考：《中國地質(zhì)大學(xué)(北京)》2015年碩士論文

【摘要】：自古有言“黃金有價,玉無價�！濒浯湓谖覈挠裎幕姓紦�(jù)重要地位,它的顏色豐富,質(zhì)地溫潤,且韌性良好,是當(dāng)之無愧的“玉石之王”。對翡翠風(fēng)化作用形成皮殼的特征研究有助于判別內(nèi)部質(zhì)量狀況,前人對其有一定程度的研究,但其形成機理研究還不夠深入。本文從廣東佛山平洲收集了不同顏色皮殼的翡翠原石,對其進(jìn)行寶石學(xué)常規(guī)測試,顯微鏡下觀察,電子探針、X射線粉晶衍射和紅外光譜和紫外-可見光光譜等測試實驗,對次生作用下翡翠的礦物組成及其化學(xué)成分特征,結(jié)構(gòu)特征和譜學(xué)特征等方面進(jìn)行研究,探討不同皮殼的致色原因及結(jié)構(gòu)的變化。電子探針測試表明樣品的主要礦物有硬玉,次要礦物有淺閃石、藍(lán)閃石等閃石族礦物。皮殼處的礦物顆粒并未改變成分,內(nèi)部礦物為硬玉的皮殼也為硬玉,而充填于顆粒間隙的次生礦物可能多為褐鐵礦、赤鐵礦和綠泥石等粘土礦物,且綠泥石中主要致色元素為Fe2+。內(nèi)部正綠色翡翠的皮殼處雖然已經(jīng)風(fēng)化為褐紅色等,但皮殼中硬玉仍含有0.1-0.2%的Cr2O3,內(nèi)部為較純的硬玉礦物。偏光顯微鏡下觀察顯示,翡翠皮殼的結(jié)構(gòu)與內(nèi)部特征具有相關(guān)性。所選取的大多數(shù)翡翠樣品皮殼與內(nèi)部礦物顆粒都為硬玉,皮殼處結(jié)構(gòu)疏松,顆粒間隙較大,顆粒間隙充填有暗色隱晶質(zhì)-微晶質(zhì)礦物,部分樣品黑色皮殼礦物顆粒表現(xiàn)為蝕變現(xiàn)象。次生油青種翡翠中可見呈細(xì)微的網(wǎng)脈狀結(jié)構(gòu)及交代殘余結(jié)構(gòu),為暗色隱晶質(zhì)礦物可能以充填或交代的形式存在于翡翠中而致色。X射線粉晶衍射測試顯示黑烏砂皮處的礦物除硬玉外,還有有綠泥石等次生礦物;紅外光譜測試圖譜顯示,黑烏砂皮翡翠和部分黃砂皮翡翠的皮殼顏色3500cm-1處有較寬且平緩的吸收峰,可能指示次生作用為主要致色原因;紫外-可見光光譜顯示正綠色翡翠的綠色部分主要為Cr3+致色,淺綠色的翡翠同時具有鐵和鉻的吸收峰,翠綠色的翡翠只有明顯的鉻吸收峰。由于三價鐵對翡翠顏色貢獻(xiàn)不大,結(jié)合探針數(shù)據(jù),可推斷翡翠淺綠色主要為Cr3+致色,翠綠色主要為Cr3+和Fe2+共同致色。
[Abstract]:Since ancient times, there has been a saying, "Gold has price, jade is priceless." Jade occupies an important position in the jade culture of our country, its color is rich, texture is warm and moist, and toughness is good, it is worthy of "King of Jade". The study on the characteristics of the weathering of jadeite jade is helpful to distinguish the internal quality, but the research on the formation mechanism of jadeite is not deep enough. In this paper, the jadeite of different color shell has been collected from Pingzhou, Foshan, Guangdong Province, and has been tested by conventional gemstone test, microscope observation, electron probe X-ray powder diffraction, infrared spectrum and UV-Vis spectrum, etc. The mineral composition, chemical composition, structural and spectral characteristics of jadeite jade under secondary action were studied. The electron probe test shows that the main minerals of the samples are jadeite, the minor minerals are amphibole, blue amphibole and other amphibole minerals. The mineral particles in the crust have not changed the composition, and the crust with the inner mineral is jadeite, while the secondary minerals filled in the intergranular space may be mainly limonite, hematite and chlorite, etc. Clay minerals, such as limonite, hematite, chlorite, etc. The main chromogenic element in chlorite is Fe2. Although the crust of the jadeite is weathered to brownish red, the jadeite still contains 0.1-0.2% Cr _ 2O _ 3 and is a pure jadeite mineral. Under polarizing microscope, the structure of jadeite shell is correlated with its internal characteristics. Most of the jadeite samples' crust and inner mineral particles are jadeite, the structure of the shell is loose, the grain gap is large, and the granular gap is filled with dark cryptic and microcrystalline minerals. Some of the black crust mineral particles are altered. In the secondary oil green jadeite, the net vein structure and the metasomatic residual structure can be seen. The results of X-ray powder diffraction analysis showed that the minerals in the black sand skin had secondary minerals, such as chlorite, in addition to jadeite, and the infrared spectra showed that, in addition to jadeite, there were some secondary minerals, such as chlorite, in the form of filling or metasomatism. There is a wide and gentle absorption peak at the 3500cm-1 of the shell color of the jadeite and part of the yellow jadeite jade, which may indicate that the secondary action is the main cause of chromogenic effect, and the UV-Vis spectrum shows that the green part of the emerald is mainly Cr3 chromogenic. The light green jadeite has the absorption peak of iron and chromium at the same time, and the emerald with emerald green has only the obvious absorption peak of chromium. Due to the little contribution of trivalent iron to the color of jadeite, it can be inferred that the light green of jadeite is mainly Cr3 chromogenic, the emerald green is mainly caused by Cr3 and Fe2, combined with the probe data.
【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】：P619.28

【參考文獻(xiàn)】

相關(guān)期刊論文 前4條

1 高媛;;紅外光譜在翡翠研究中的應(yīng)用[J];紅外技術(shù);2008年07期

2 陳洪起;趙杏媛;;一種定量測定粘土礦物的X射線衍射方法[J];礦物巖石;1989年04期

3 閆薇薇;王建華;;緬甸第三紀(jì)斷陷盆地中的次生油青種翡翠的形成機理研究[J];礦物巖石;2013年01期

4 劉顯凡;汪靈;李慧;劉菁;趙甫峰;盧秋霞;胡琳;;角閃石族和輝石族礦物的系統(tǒng)礦物學(xué)分類命名[J];礦物學(xué)報;2015年01期

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本文編號：1822857