Study On The Genesis Of Nanhong Agate From Meigu, Liangshan,Sichuan Province

Nanghong Agate is a kind of cryptocrystalline quartz jade.Sichuan Meigu Nanghong Agate while digging later found, but in the big block, high yield, tuft split less famous become antiques and collectibles industry is new bestow favor on. Nanghong Agate color gorgeous, known to the Chinese people in hot pursuit of the " China Red ", mainly divided into red brocade, persimmon red(yellow), roses red, stripe red, cherry red, and southern Sichuan Meigu Nanghong Agate include more characteristics of icy floating flowers, Fructus and other varieties.This report mainly through microscopic magnifying observation, cathodoluminescence, infrared spectroscopy, electron probe, the micro Raman spectroscopy,xrd, poor thermal analysis techniques of Sichuan Liangshan area Sichuan Meigu Nanghong Agate color causing mechanism is studied. And Baoshan Yunnan Nanghong Agate, the Warring States period of red agate, African red agate, red agate, dyed agate for a comparative analysis, and comprehensive market survey, production characteristics and other factors, and then put forward the evaluation criteria.Microscopic observation revealed that the inclusions of Sichuan Liangshan area south of red agate red dot(also known as "cinnabar") or a ribbon wrapped body, a square or not regular shaped white inclusions and electron probe experiment can be confirmed respectively for iron oxide, calcite and barite,, according to the Raman spectra of the RBI analysis shows that, the main component of cinnabar hematite also contain a small amount of goethite. Therefore, hematite and hematite inclusions are the cause of the red agate red.Sichuan Liangshan area south of Onyx is colored by inclusions, single polarizing 20 times larger case, "cinnabar" size, depth, distribution of is different in different samples, different positions of the same sample is also different. "Cinnabar" diameter main 5-50 μm, in some samples showed uniform size distribution, some is size and distribution is not uniform. Since the research direction is red, most of the selected samples have no bands. But the observation of thin sections, a few bands were observed for light or dark strips with irregular. The presence of cryptocrystalline dip and along the fissures deepen phenomenon: enlarged 20 times observed, as can be seen in trace of color but could not be observed mineral inclusions granules, speculated that inclusions aphanitic; there are still coloring matters in fractured enrichment phenomenon can be inferred aphanitic part of the color is secondary. Wu Shi sample sheet "cinnabar" more more intensive distributed; some group sheet aggregation, and colors are yellow, different shades of red, opaque even; there are also varying degrees of blooming phenomenon.The differential thermal analysis of water loss curve that Sichuan Liangshan area south of red agate formation temperature, formation of further infer "cinnabar" and coloration mechanism.