Study On The Feldspar From Gu Yang County, Intermogolia And Their Color Enhancement

Feldspar is of middle-class gemstone. The most familiar gem-quality feldspar ismoonstone, adularia, amazonite, sunstoe and labradorite.These gem are opacity.Transparent feldspar is the rare kind of feldspar group. It is reported that sometransparent feldspar cystals were found in succession in Anhui,Guizhou of China, aswell as in USA,Mexico,Congo. In this paper, the research subject is transparent gemfelspar from Gu yang County, Intermogolia Antonymous Region, and its gem mineralfeatures are also elaborated.Based on references of prolific materials of predecessors, much detailedinformation of labradorite was summarized, especially the distribution characteristicsof transparent feldspar in the world. Besides, the formation conditions of labradoriteproduced in Guyang was also investigated . According to the research orientation ,samples and specimens were selected and analyzed by advanced equipment. With Xray powders diffraction and infrared measurement ,the mineral category and its crystalstructures were inferred. With electron micro probe, the chemical composition wasobtained, and the category and number of feldspar was calculated.At present, the research for the color causes of feldspar is rarelyconducted .Based on predecessor's literatures, the color causes of Guyanglabradorite were thoroughly probed with research method for sapphire and othertransparent gems .Quantitative examination was made on Guyang labradorite withultraviolet-visible light-infrared spectrophotometer and computer controlled colormatch instrument. Based on predecessor's theory , by means of spectrum absorbresearch it is concluded that some places of tetrahedron in labradorite occupied byFe3+ and Fe2+cause its present color .Labradorite produced in Guyang appears in crystal form with high transparency ,which is big in size (0.1-5cm) ,light yellow ,brilliant but too pale in color. It is easyto cut with high finished percentage. Now there is a very good market for beautifulnatural gemstones, while production of natural gemstone is declining year by year. Tosolve the contradiction, the effective way is improvement. Therefore, the colorimprovement of Guyang labradorite become my research orientation. It is expected toimprove its color with radiation and thermal process so that its economic value can beraised. Furthermore, the mechanism of color improvement was probed.