Weathered Cortex of Eluvial–Deluvial Jadeite Jade from Myanmar: Its Features, Formation Mechanism, and Implications

Myanmar is the principal provider country of high-quality jadeite jade in world, including so-called primary and secondary stones. The stones occur as rounded pebbles, boulders, blocks eluvium–alluvium often hold varying degrees weathering. Unlike common rocks, such granite, gabbro, schist, gneiss, amphibolite, frequently have weathered cortexes that vary appearance, depth, texture, mineral components compared with those inner bodies. In this study, representative samples eluvial–deluvial were selected, their appearances, textures, components, chemical composition features analyzed. Their red, yellow, white, or black, 0.01–1.80 cm thick. opaque, soil luster a fansha phenomenon. body was usually translucent, green white color. Along border between cortex certain stone, textures same for successive grain sizes. only difference there more cracks, cleavage planes, fissures cortex. Jadeite main component both; however, minor late-stage supergene minerals (such gibbsite, kaolinite, halloysite) Fe-bearing colloidal identified along boundaries Studies gemmological applications identification grading raw jadeite, well its design carving. Moreover, studies might provide information improving our understanding unique weathering processes monomineralic aggregates relative to multiple-mineral gambling pieces through analyzing