Another suggestion is that the color might be related to ice with high levels of metallic compounds, including copper and iron.

另一种说法是，这种颜色可能与冰中含有的大量金属化合物有关，包括铜和铁。

youdao

Copper and iron coexist.

铜、铁共生规律。

youdao

Valve Properties Bronze, Brass, Copper and Iron.

阀门特性，青铜，黄统，红铜和铸铁。

youdao

The iron and copper helmet was probably used for ceremonies.

VOA: special.2010.08.04

The company's output of iron ore, as well as copper, zinc and nickel, surged in the last three months of 2009 because of strong demand from Chinese carmakers and construction companies.

VOA: standard.2010.01.21

State-owned companies are bargain-hunting for copper and iron ore in more stable places like Zambia and Liberia.

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