PYROPE FROM YUNNAN PRPOVINCE, CHINA

Red pyrope is one of the most important gem resources in Yunnan. The pyropes from Yunnan Province, which are characterized by the large grains, less cracks and high production, have been sold very well in the world market for over a decade since they were mined. The pyropes are found in the Neogene subvolcanic basaltic breccia pipe. The rubbles and crystals of pyrope and chrome-diopside which can be used as gem materials are found in the breccias whose component is very complex. The breccias which are subjected to weathering can become gem deposit. The research shows that Cr³⁺ ion is responsible for the red color of pyrope. According to the content of Cr³⁺ ions in the pyrope, the pyropes can be divided into three types: chromium-bearing pyrope, microchromiun-bearing pyrope and pyrope.