摘要:
近一段时间来，大量来自老挝的“老挝石”进入福州寿山石原石市场，给福州的寿山石市场造成较大的冲击。笔者收集了福州市场上部分“老挝石”样品，采用X射线粉末衍射（XRD）、中红外光谱（MIR）和近红外光谱（NIR）等测试方法对“老挝石”样品的外观特征、矿物组成及鉴别方法进行初步研究。研究表明，“老挝石”样品的相对密度为2.52～2.60，微透明—半透明，颜色以白色、红色、粉红色为主，黄色较少，颜色不及寿山石丰富明快。“老挝石”样品的矿物组成包括高岭石、地开石和珍珠陶石，未见叶蜡石和伊利石；含高岭石的“老挝石”样品多为红色或浅红色，透明度较差，类似于寿山石中的善伯石等品种；由有序度较高的地开石组成的“老挝石”样品颜色较浅，透明度较高，与寿山石中的一些坑头石和高山石品种接近；以珍珠陶石为主的“老挝石”样品颜色较浅，多为白色，透明度较好，半透明，而在寿山石中含珍珠陶石的品种很少。“老挝石”的矿物组成与寿山石中的高山石类相似。但是，高山石类寿山石的大多数品种以地开石为主，而“老挝石”样品中含高岭石的占多数。这可能是寿山石与“老挝石”在矿物组成上的重要区别。在鉴别“老挝石”时，应十分注意这一点。近红外光谱分析可以鉴别高岭石，有可能为“老挝石”的鉴别提供一种快速简便的现场无损检测方法。褪色实验表明，在通常条件下，光照不会使“老挝石”产生明显的褪色现象。一些石商反映的褪色现象，或许与“老挝石”表面所含的水分有关。
Abstract:
Recently a large number of Laos stones from Laos has appeared and impacted on the larderite market in Fuzhou.Several samples of Laos stones were collected in the Fuzhou market and were analyzed by X-ray powder diffraction (XRD),mid-infrared spectroscope(MIR)and near-infrared spectroscope(NIR).The study result shows that Laos stones have the relative densities of 2.52-2.60,translucent to subtranslucent,and the colour is red,white,pink and seldom yellow.Laos stones consist of kaolinite,dickite and necrite.Phyrophyllite and illite have not been found in Laos stone samples.The Laos stone samples those composed of kaolinite have red or pink colour and less transparence,which are similar to the characteristics of Shanbo stone in larderite.The Laos stone samples those composed of dickite show a light colour and better transperance,which are similar to Kentou stone and Gaos-han stone in larderite.The Laos stone samples those composed of nacrite also are white and translucent.The Laos stones are similar to Gaoshan group of larderite in their mineral components.However,there is an obvious difference between them.Kaolinte containing in most samples is the most important feature of Laos stone,which is different from dickite containing in most larderites.NIR could be a convenient and nondestructive testing method for identifying Laos stones.Colour fading of Laos stones has been said.Fading test for some Laos stones,however,demonstrates that most samples do not fade after lighting,and the colour of some Laos stones being lighter may be attributed to the water containing on the surface of the stones.
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