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(1) When selecting a d iamond , check for blackspots or impurities, type and fineness of cut with an eye-glass.选购钻石的时候,最好是用放大镜细察是否有黑点或其他瑕疵,并注意其类型及割切的工夫。(2) Good jade should be "translucent" in appearance, and feel cold-to-the-touch.好的玉块应该是半透明的,即