危地马拉"永楚料"翡翠的宝石学特征
Gemmological Characteristic of"Yongchuliao"Feicui(Jade)from Guatemala
徐世龙 1杨九昌 1陈全莉2
作者信息
- 1. 中国地质大学(武汉)珠宝学院,湖北武汉 430074;湖北省珠宝工程技术研究中心,湖北武汉 430074
- 2. 中国地质大学(武汉)珠宝学院,湖北武汉 430074;湖北省珠宝工程技术研究中心,湖北武汉 430074;滇西应用技术大学珠宝学院,云南保山 679118
- 折叠
摘要
危地马拉"永楚料"翡翠是近年来中国翡翠市场上出现的新品种,其颜色多为深绿色.本文收集了 4件危地马拉"永楚料"翡翠成品和1件原石样品,在常规宝石学测试的基础上,通过红外光谱、激光拉曼光谱、紫外-可见光谱和电子探针等测试技术对其化学成分、谱学特征和颜色成因等进行了分析与讨论.结果显示:危地马拉"永楚料"翡翠样品的折射率为1.66～1.67(点测),相对密度为3.33～3.34,玻璃光泽,长短波紫外光下均为荧光惰性;红外光谱表明样品的主要矿物为绿辉石,成分均匀;拉曼光谱表明样品中的绿辉石为P2/n型结构,其他物相包括榍石和无定形碳,榍石常具"网脉状"截面;紫外-可见光谱出现437 nm和636、658、688 nm处吸收峰,分别由Fe3+和Cr3+所致."永楚料"翡翠在 自然光下的体色由Cr3+主导,Fe2+以及Fe2+—Fe3+间的电荷转移参与影响;电子探针计算得出"永楚料"翡翠中绿辉石的平均化学式为(Na0.50 Ca0.49)0.99(Mg0.46Fe0.08Al0.48Cr0.01)1.03[(Si1.99Al0.01)2O6]."永楚料"翡翠样品更富 Mg 贫 Fe 元素,其更高含量的Cr元素及副矿物以榍石为主的特征有别于危地马拉和缅甸墨翠.
Abstract
In recent years,a new variety of Feicui(also translated as jade)named"Yongchul-iao"has emerged in Chinese markets.This kind of Feicui with a dark green colour is from Guatemala.In this study,the authors collected 4 pieces of"Yongchuliao"products and 1 piece of rough stone.The conventional gemmological characteristics,chemical composi-tion,spectral characteristics,and colour origin of the"Yongchuliao"samples have been test-ed,analyzed and discussed through infrared absorption spectra,laser Raman spectra,UV-Vis spectra,and electron probe micro-analysis,respectively.The results showed that the re-fractive index of"Yongchuliao"samples falls between 1.66-1.67(point measurement),with a specific gravity of 3.33-3.34,presenting a glass luster and inert fluorescence under both long wave and short wave ultraviolet light.Infrared spectra revealed that the main min-eral of the"Yongchuliao"samples are omphacite,and the composition of omphacite has re-markable consistency.Raman spectra showed that the crystal structure of this type of om-phacite is P2/n,and other phases in"Yongchuliao"samples include titanite and amorphous carbon.Moreover,titanite often has a"reticulated cross"section.UV-Vis spectra exhibited characteristic peaks at 437 nm(caused by Fe3+),and 636,658,688 nm(caused by Cr3+).And the colour of"Yongchuliao"under natural light is primarily influenced by Cr3+and is also affected by both Fe2+and the charge transfer between Fe2+and Fe3+.The average chemical formula of"Yongchuliao"according to the results of electron probe micro-analysis is(Na0.50Ca0.49)0.99(Mg0.46 Fe0.08Al0.48Cr0.01)1.03[(Si1.99 Al0.01)2 O6].In addition,"Yongchul-iao"is richer in Mg and poorer in Fe.A higher content of Cr makes it distinguishable from Guatemalan Mocui."Yongchuliao"with only titanite as its accessory mineral is also different from Mocui from Myanmar and Guatemala.
关键词
"永楚料"翡翠/绿辉石/宝石学特征/危地马拉Key words
"Yongchuliao"Feicui(jade)/omphacite/gemmological characteristic/Guatemala引用本文复制引用
基金项目
中国地质大学(武汉)珠宝学院开放基金(CIGTXM-04-S202305)
云南省本科教育教学改革研究项目(JG2023143)
出版年
2024
NETL
NSTL
万方数据