新西兰碧玉的宝石矿物学特征研究

发布时间：2018-04-25 03:36

本文选题：新西兰 + 碧玉　；参考：《中国地质大学(北京)》2015年硕士论文

【摘要】：新西兰碧玉受国家政策保护,原料不允许出口,只有加工成成品后才可以销售和出口,新西兰碧玉的商业发展史仅有30年左右。进入中国市场时间短暂,却因其颜色鲜艳、少水线、独特的黑点和绿点设计深受消费者喜爱。前人对新西兰碧玉的研究较少,且研究样品均来源于市场,具体产地不确定,未对新西兰碧玉的宝石学特征进行全面的分析研究。本文在获取了准确产地样品的基础上,运用电子显微镜、扫描电镜、电子探针、X射线粉晶衍射、红外光谱分析、微量元素测试等现代测试方法对新西兰碧玉的矿物学和宝石学特征进行了较为全面的研究。新西兰碧玉矿物矿区位于新西兰南部地区,其原生矿为蛇纹岩型矿床,呈透镜体形式产出,由超基性岩蚀变而成。偏光显微镜下观察,新西兰碧玉的主要成分为透闪石,杂质矿物为钠长石、绿泥石、辉石以及砷镍矿。透闪石颗粒细小,为纤维交织结构。按粒度相对大小可分为斑状变晶结构;按矿物颗粒大小分为细粒变晶结构和微粒变晶结构;按矿物的结晶习性、形态及矿物颗粒之间的关系分为毛毡状变晶结构、显微片状变晶结构、束状变晶结构及脉状结构。构造主要为块状构造,颗粒均向展布,不见片麻理、片理、线理等方向性构造。电子探针分析结果表明新西兰碧玉的主要矿物成分为透闪石,杂质矿物为钠长石、绿泥石、辉石及砷镍矿。X射线粉晶衍射的结果与透闪石的标准谱一致;部分样品中显示钠长石以及粘土矿物的衍射峰,未显示砷镍矿以及辉石的衍射峰,说明含量可能不到1%。扫描电镜显示,碧玉样品中质地最好、韧性最强、最不易断裂和破碎的结构为毛毡状变晶结构,因为毛毡状结构中裂纹最不容易扩展。LA-ICP-MS实验发现,Cr元素和Ni元素含量越高的样品,其绿色越鲜艳。红外光谱分析结果表明各地区碧玉之间红外光谱大致相似,但存在微小差别。
[Abstract]:New Zealand Jasper is protected by national policy, raw materials are not allowed to export, only processed into finished products can be sold and exported, New Zealand Jasper business history of only about 30 years. Enter the Chinese market for a short time, but because of its bright colors, less waterline, unique black spots and green dot design by consumers. The previous researches on New Zealand Jasper are few, and the samples are all from the market, the specific origin is uncertain, and the Gemological characteristics of New Zealand Jasper have not been comprehensively analyzed. In this paper, on the basis of obtaining the exact samples from the origin, the X-ray powder diffraction and infrared spectroscopy were used to analyze the samples by means of electron microscope, scanning electron microscope, electron probe diffraction and X-ray diffraction. The mineralogical and gemological characteristics of New Zealand Jasper were studied by modern testing methods such as trace elements. The Jasper mineral deposit of New Zealand is located in the southern part of New Zealand. Its primary ore deposit is ophiolite type deposit, which is formed by ultrabasic rock alteration in the form of lens. Under polarizing microscope, the main composition of New Zealand Jasper is tremolite, impurity minerals are albite, chlorite, pyroxene and arsenic nickel. The tremolite particles are fine and interwoven. It can be divided into porphyry structure according to the relative size of grain size, fine grain structure and particle structure according to the size of mineral particle, and felt-shaped structure according to the crystallization habit of mineral, morphology and the relation between mineral particles. Microflake structure, bundle structure and vein structure. The structure is mainly block structure, grain distribution, missing lamellae, lamellar, linear and other directional structures. The results of electron probe analysis show that the main mineral composition of New Zealand Jasper is tremolite, and the impurity minerals are albite, chlorite, pyroxene and arsenicite. The X-ray powder diffraction results are consistent with the standard spectrum of tremolite. Some samples show diffraction peaks of albite and clay minerals, but no diffraction peaks of arsenicite and pyroxene, indicating that the content may be less than 1. Scanning electron microscope (SEM) showed that the texture of Jasper sample was the best, the toughness was the strongest, and the structure most difficult to fracture and broken was felt-shaped metamorphic structure. It is found that the higher the content of Cr and Ni, the brighter the green of the samples with the lowest crack propagation in the felt-like structure. LA-ICP-MS experiment shows that the higher the content of Cr and Ni is, the more bright the green is. The results of infrared spectrum analysis show that the infrared spectra of Jasper in different regions are similar, but there are slight differences.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P619.28

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