Under UV light, clean sand appears purple or black. Some minerals, such as calcium carbonate in seashells, glow blue, as does a shovel handle in the picture above.
紫外线照射下，干净的沙子呈紫色或黑色。有些矿物，如海贝中的碳酸钙，会闪着蓝光，就如同上图中的铁锹的把手。
Under UV light, clean sand appears purple or black.
紫外线照射下，干净的沙子呈紫色或黑色。
Under UV light, tar from the Gulf of Mexico oil spill lights up orange-yellow on the beaches of Gulf Islands National Seashore (picture) while clean sand glows purple in a long-exposure picture.
长曝光拍摄的图片中，大片的油污在紫外线下发出橙黄色的光，干净的沙子为紫色。这是海湾岛国家海滨沙滩上的情景。
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