| As the xenoliths of kimberlite, diamond crystallized in the ancient mantle. It is thehardest natural mineral, and one of the world’s most precious gems. Diamond’s highthermal conductivity makes it to be used in many applications technology as avaluable industrial component.Kimberlite is the world’s most important diamond-bearing rocks, which contain avariety of indicator mineral for diamonds. So it is very important to studymineralogical characteristic of kimberlite for finding diamond mines. In this paper,The testing skills include Microscopic observation, EPMA and X-ray diffractionanalysis.By observing hand specimens and rock flakes, most of the kimberlites haveporphyritic texture, and they all have been serious alterated, it is difficult to find theprimary minerals. Garnet, mica, calcite, feldspar, and a variety of metallic mineralscan be found in it, the girdles are obviously.By EPMA and X-ray diffraction analysis, Some more minerals have been found:chromite, perovskite, magnetite, zircon, apatite and Pennine. After calculating theformulas, we also identified the mineral species of garnet, mica, serpentine andchlorite. X-ray diffraction analysis detected moissanite and graphite, which haven’tbeen observed in rock flakes.Girdle and paragenetic associationsymbiosis are very common in these rock flakes,for example: andradite-serpentine girdle, chromite–andradite–magnetite girdle, zircongirdle and chalcopyrite–pyrite paragenesis, perovskite–symbiotic paragenesis.According to the information, the genesis of chromite–andradite–magnetite girdle hadseveral steps: after chromite and pyroxene formed pyrope in the condition of UHPmetamorphic, pyrope alteration into andradite, then the edge of andradite had beenaltered to magnetite. Suddenly changes of the environment caused the formation ofzircon girdle.The formation temperature of chlorite is from145°C to147.92°C. To chromite, theformation temperatureis between1577K and1611K, and its formation pressure isfrom40Kbar to55Kbar. |
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