翡翠的矿物组成特征及其质量

通过翡翠的矿物组成研究 ,其主要由辉石族的矿物 (硬玉、绿辉石、霓石、钠铬辉石 )组成 ,还有少量的闪石族矿物、长石族矿物以及绿泥石和铬铁矿、褐铁矿、赤铁矿等组成 ,他们的含量变化直接影响着翡翠的种类。在矿物组成中 ,硬玉呈不同的绿色 ,这些颜色的多少与分布特征直接影响着翡翠的颜色特征和档次。绿辉石、钠铬辉石含量少 ,在翡翠中呈黑绿色 ,它们的存在使翡翠的档次降低。闪石族矿物主要是蓝色的钠铝质闪石 ,翡翠中的飘“蓝花”就是由于它们造成的。长石族矿物主要是钠长石 ,颗粒细小 ,在翡翠中其含量 1.0 %～ 8.0 %。翡翠中主要的矿物形态以粒状为主 ,矿物的颗粒越细 ,翡翠的透明度、质地也越好。建议将翡翠定义为 :“在地质作用过程中主要由钠质或钠钙质辉石组成的达到玉级的集合体。”

MINERAL COMPOSITIONS CHARACTERS OF FEICUI AND ITS QUALITY

Mineralogical characters of feicui were studied. The results shown that it is composed by pyroxene group mineral (jadeite, omphacite and uryite) mainly, and a small of amounts amphibole group and feldspar group mineral, chlorite etc. The types of feicui are influenced by the contents of minerals. The color amounts and colors distribution characters of jadeite influenced directly the colors and the grads of feucui. The colors of feicui were influenced by omphacite and uryite; they made feicui grad lowed. The "blue flower" on feicui was formed by a small amounts of amphibole group minerals( Na-Al amphiboles) Feldspar group mineral is albite , its affect is that the transparency is increased for feicui. The shapes of mineral grains is the granular mainly in feicui, the smaller the mineral grains, the better the quality of feicui.