BACKGROUND A new deposit type with a scheelite-beryl-molybdenite assemblage was first discovered in the Zhen'an area of Shaanxi Province.
BAOBJECTIVES The research on chromatic mechanism and genetic mechanism of emerald was carried out.
METHODS Combined with the geological survey, Electron Microprobe and in-situ Micro X-ray Diffractomer were used to conduct mineral research.
RESULTS The emerald mainly occurs in the quartz (calcite) veins as euhedral crystal and is associated with scheelite. Both the core and rim of the emerald with high V2O3 contents of 0.64%-0.98% and 1.04%-1.42%, respectively, show an increased V2O3 trend from core to rim. Diffraction data show that the emerald is normal beryl and has two kinds of isomorphous substitution mechanism, Al↔Me2+ and Be↔Li. Vanadium is the main coloring element of emerald and was mainly derived from carbonaceous slate, mica schist, and dolomitic marble, whereas Be, Si and Al were derived from deep acidic igneous rocks.
CONCLUSIONS The discovery provides basic geological data for the comprehensive development and utilization of tungsten and antimony mineral resources in the deposit, and indicates new prospecting directions for continued searching for rare metal deposits in the region and deep areas of the South Qinling.