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Mineralogy
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Descriptive Mineralogy
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Streak Test
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The rubbing of an unidentified mineral against an abrasive tile (usually ceramic) because that the function of evaluating the colorof the small grains scraped off. The streak check is advantageous as a diagnostic in many instances because, in naturallyoccurring crystals, the large particle size renders them opaque, creating a dark color. Crushing the particles right into asmaller size allows their "true" colour to it is in seen. The method does no work, however, for part extremelyfine-grain minerals such as magnetite.