On the basis of lab researches performed in 2009 for the gemmological properties and compositions of peripheral materials of the red of Tibet,the investigation team of National Gemstone Testing Center,China(NGTC) performed a field investigation on occurrence of international disputing about red of Tibet from the geology,mineral deposit,stratigraphy and geomorphology at the border area between Bailang county and Jiangzi county in Shigatse,Tibet(E29°04′01.5″,N89°20′54.8″) in May,2010.The investigation team interviewed the villagers of Mencuo and Zhalin villages,viewed the trade process and collected the red feldspar samples.The results show that the majority of red feldspar samples in the field were artificially placed on the ground surface and in the loose ground,which supports the previous deduction of lab researches in 2009.

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.