"翠花玉"的宝石学特征及矿物组成

近期,珠宝市场上出现了一种商业名称为"翠花玉"的呈紫色、绿色和白色的玉石,容易被误认为是和田玉.为了查明其矿物组成及宝石学特征,笔者选取了3块样品,对其进行了常规宝石学测试和偏光显微镜下的观察,并用X射线粉晶衍射法和电子探针测试等分析方法,重点对"翠花玉"样品的矿物组成进行了研究.结果表明,"翠花玉"样品为多矿物集合体玉石,为交代成因产物,主要矿物组成为透辉石、透闪石、萤石、石英、斜长石、方解石,其中透闪石多呈网脉状分布.绿色部分折射率为1.61(点测),紫色部分折射率为1.43(点测),平均密度为3.03 g/cm³左右.样品颜色主要由紫色的萤石和绿色的透闪石致色.

Gemological characteristics and mineral components of "Cuihua Jade"

Recently, a new kind of gem product whose business name is "Cuihua Jade" appears in the jewelry market. It contains purple, green and white parts and is easily mistaken for nephrite. The authors chose three samples, used conventional gemological methods and polarizing microscope to investigate their gemological characteristics and mineral components, and then employed XRD and EPMA to emphatically probe into their mineral components. The results show that the "Cuihua Jade" is a kind of multi-mineral aggregate jade and of metasomatic origin, with its main mineral components being diopside, tremolite, fluorite, quartz, plagioclase and calcite, in which the tremolite exhibits network distribution in the sample. The refractive index of the green part is 1.61 (point measurement), and that of the purple part is 1.43 (point measurement). The average density is about 3.03 g/cm³. The color of the sample is mainly caused by purple fluorite and green tremolite.