翡翠中钠铬辉石的矿物学特征研究

Mineralogical Characteristics of Ureyite in Jadeite Jade

摘要: 采用电子探针、X射线衍射和吸收光谱分析研究翡翠中钠铬辉石的矿物学特征。结果显示,钠铬辉石与翡翠呈共生关系;其分子式为(Na_0.83Ca_0.02)(Cr_0.78Al_0.10Fe_0.08Mg_0.02) Si_2.06O₆;晶胞参数 a=9.530 Å,b=8.672 Å,c=5.264 Å,β=107.51°,V=414.88;密度为3.55g/cm³;钠铬辉石中Cr³⁺的晶体场跃迁决定了其具有深浅程度不同的绿色调。

Abstract: In the paper, mineralogical characteristics and compositions of ureyite in jadeite jade are studied by using EPMA, X-ray diffraction and absorption spectroscopy analysis.The results show that ureyite is paragenous with jadeite jade, and the chemical formula of ureyite is(Na_0.83Ca_0.02)(Cr_0.78Al_0.10Fe_0.08Mg_0.02) Si_2.06O₆.The unit cell parameters of ureyite are a=9.530 Å, b=8.672 Å, c=5.264 Å, β=107.51°, V=414.88 and the density is 3.55g/cm³.Different shades of green in ureyite are related to the crystal-field transition frequency of Cr³⁺.