Characteristics of Surrounding Rocks and Surface Residues of“Red Feldspar from Tibet”

Since 2008, whether the“red feldspar from Tibet”exists and whether such a stone is diffusedly-treated have been hot-debated issues in the gemmology communities at home and abroad.The gemmological characteristics of the surrounding rocks and the surface residues of the“red feldspar from Tibet”are studied presently by using the polarizing microscope, electron microprobe and X-ray photoelectron spectroscopy techniques.The results show that the original host rocks of the“red feldspar from Tibet”are composed mainly of intermediate-basic intrusive rocks containing glasses and bubbles, and that the surface residues of the red feldspar and its surrounding rocks contain plenty of copper and iron.Furthermore, the surrounding rocks and surface residues may have artificially been sintered at a high temperature in their later development stage.In this sintering process, part of dark minerals and some foreign substances such as co-solvents turned into glasses and bubbles.Further tests reveal that the majority of the“red feldspar from Tibet”samples under investigation might have been copper-diffusedly-treated.