This sediment layer is enriched in the rare metal iridium and other elements that are relatively abundant in a meteorite but very rare in the crust of Earth.

这一沉积层富含稀有金属铱，以及其他在陨石中较丰富而在地壳中十分罕见的元素。

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There is metallization of rare elements in some of the granite bodies.

其中某些岩体发育有稀有元素矿化。

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Uses: used as glass etching agent, metal surface of the chemical polishing agent, wine of the disinfectant, preservative, mordant the fiber is also used for extraction of rare elements and so on.

用途：用作玻璃蚀刻剂，金属表面的化学抛光剂、酿酒的消毒剂，防腐剂，纤维的媒染剂，也用于提取稀有元素等。

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The plant is finally operating, but prices for some rare-earth elements are now 80% off their peaks.

WSJ: Mining Firm, Ex-Teacher Battle Over Rare Earths

The two superpowers are competing over a valuable new resource -- the rare earth elements used in the construction of nearly all smartphones, tablets and other electronic gadgets.

CNN: The future world of 'Call of Duty: Black Ops II'

Metals, platinum-group elements, rare earth elements, and other volatiles, like H, H2O, and carbon compounds, are abundant on asteroids, many of which are relatively accessible from Earth.

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