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Secondary Changes And Their Gemological Significance Of Jadeite

Posted on:2012-03-17Degree:MasterType:Thesis
Country:ChinaCandidate:X WuFull Text:PDF
GTID:2250330401479816Subject:Mineralogy, petrology, ore deposits
Abstract/Summary:PDF Full Text Request
Jadeite stands a unique very important species of the jewelry family for its smooth andtough nature, beautiful colors and the long-history culture. Based on the coloringmechanism, the color of jadeite is usually divided into two groups: the protomer color andthe secondary color; the latter includes color systems of yellow, red, celadon-deep greenand celadon-bluish green. Although the study of jadeite has advanced into a new fruitfulstage in aspects of Mineralogy, Petrology, Deposit Geology as well as cultural origins andmodern crafting techniques, the development of secondary formation and modification ofjadeite is still lack of full attention that there are no systematic conclusions. This work is thevery complement focuses on the secondary minerals in jadeite based on several typicaljadeite samples.The structure features, the existence form of secondary minerals and the compositionof the jadeite samples are the three principle contents in this study. Modern testingtechniques were applied, FT infrared micro-spectroscopy and the combination of EMPAand optical spectroscopy for example. The way of filling and metasomatic of varioussecondary minerals was firstly investigated with both naked eyes and crossed nicols; andthen the properties of the secondary minerals were determined by infraredmicro-spectroscopy, based on which, the classification of the secondary minerals wasobtained in combination with the EMPA results. It is found that the supergene geochemicalzoning features around watertable in weathering areas gives the jadeites a vertical-bandingcoloring through different secondary minerals generated in the river terrace deposit. Thewhite conglomerations and veins in the open fissures originates from the interlacing ofkaolinite; the yellow and red secondary minerals in the jadeite samples are mostly thelimonite while celadon-deep green and celadon-bluish green minerals mostly the diabantite;and the generally accepted iron-manganese oxides are indeed another form of diabantitebeing.In addition, novel secondary minerals of paracelsian and agrellite were detected in theEMPA tests, and therefore investigation on the origin and ccurrence of the two was carried.
Keywords/Search Tags:Jadeite, Secondary minerals, Gemological research
PDF Full Text Request
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