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Gemmological And Mineralogical Studies On Characteristics Of Hydrogrossular Jade And Vesuvianite Jade From Tawmaw Area, Burma

Posted on:2015-02-27Degree:MasterType:Thesis
Country:ChinaCandidate:Y R XuFull Text:PDF
GTID:2250330428469277Subject:Unknown
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Several kinds of jade which possess similar extrinsic features with jadeite hasreached the Chinese jewellery market recently. The colour of these jade materialsvaries from brownish-yellow to vivid green. These jade materials resemble jadeitefrom the appearance of rough stone, the luster of polished stone, density and hardness.This dissertation studied two analogous jade to jadeite jade whose origin are boththe Tawmaw area,Burma. The testing result indicates that the composition of thesetwo samples are hydrogrossular garnet and vesuvianite respectively.Since the study ofhydrogrossular garnet and vesuvianite jade is amount to blank, the authorendeavoured to make a thorough inquiry into the gemmological and mineralogicalcharacteristics of these two gem material.The hydrogrossular jade sample from Tawmaw area possesses a white outersurface with a dense massive clusters and grayish green, semi-transparent interior.But weighs more sedate. Dark green dot-like inclusions can be observed. It has arefractive index of1.73and a relative density of3.46. When exposed to Charlescolour filters the colour turns out to be flesh red. It can be distinguished with jadeitejade from RI, density and Charles colour filters. The vesuvianite jade sample fromTawmaw area possesses a pale yellow outer surface with a dense massive clusters andyellowish green, semi-transparent interior. It has a refractive index of1.72and arelative density of3.46. When exposed to Charles colour filters the colour maintainsgreen. Vesuvianite jade is difficult to distinguish from jadeite with the unaided eye.The chemical composition of hydrogrossular jade and vesuvianite jade isdetermined X-ray powder diffraction, infrared spectroscopy, Raman spectroscopy andelectron microprobe. The major composition of hydrogrossular jade is hydrogrosslarand the minor compositions are vesuvianite and calcite. The dark green spot is notreported magnetite but the results from aggregation of iron produced by chloritization of hydrogrossular. The major composition of vesuvianite jade is vesuvianite and theminor compositions are hydrogrossular、talc and spinel.Microscope and scanning microscope is applied to reveal the microstructue ofthese two materiasl. The mineral grains performs a relatively perfect crystal forms.Both of the material displays a granular texture and the crystal grains are disorderlyoriented.The weakest texture has the highest degree of order. The cracks in this kindof texture are most easily to expand. This feature make the hydrogrossular jade andvesuvianite jade hard to cut and process.Hydrogrossular jade and vesuvianite jade were formed during the rodingitizationof serpentinite rocks in this area. Diallage and anorthite were metasomatised by theCa-rich fluids thus hydrogrossular and vesuvianite formed. The MgO and FeOcomposition were supplied by diallage or other minerals and fluids from the theultramafic rocks available.Both hydrogrossular jade and vesuvianite jade pocess fine texture, fewer fissures,color uniformity. In terms of hardness, lustre and other characters, both are superiorto many other jade. They can be developed as new jade species and applied into themarket.
Keywords/Search Tags:Burma, jadeite, hydrogrossular, vesuvianite, rodingite
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