贵州罗甸软玉的宝石矿物学特征

近期,中国贵州省罗甸县发现了一种新的软玉矿。为了验证贵州罗甸软玉的矿物组成,采用ICP-MS,XRD及FTIR等测试仪器对该软玉样品进行了测试与研究。结果表明,贵州罗甸软玉主要由透闪石组成,含少量的方解石细脉及燧石团块;其折射率、密度与标准的透闪石接近,但普遍略低于新疆和田玉的。为了进一步评估贵州罗甸软玉的质地,运用SEM观测其显微结构,揭示其透闪石主要呈纤维状、柱状和片状变晶结构,晶粒（片）粒度小,结构细腻,具有较好的加工性能。XRD慢速扫描结果显示,贵州罗甸软玉中透闪石矿物的结晶度相对较高,推测可能与其相对稳定的结晶环境有关。

Gemmological and Mineralogical Characteristics of Nephrite from Luodian,Guizhou Province

A new kind of nephrite deposit has been discovered in Luodian County,Guizhou Province recently.In order to verify the mineral components of the nephrite from Luodian,Guizhou Province,this paper investigates this kind of nephrite samples by using the ICP-MS,XRD and FTIR.The results show that the nephrite from Luodian,Guizhou Province is mainly composed of tremolite with minor calcite veins and glaebule chert.The refractive index and density of the nephrite samples,quite close to those of the standard tremolite,are generally lower than those of the nephrite from Hetian,Xinjiang.Based on the SEM observation,the tremolite in the nephrite samples from Luodian,Guizhou Province has fibrous texture,columnar texture and sheet-like texture.The characteristics of fine grains and compact structure make the nephrite samples have good process properties.The result of XRD slow scanning shows that the crystallinity of the tremolite in the nephrite samples from Luodian,Guizhou Province is comparatively high,which are probably related with a stable crystalline environment.