Scientists have found that blackening the element using lasers can transform the metal's properties.

BBC: Copper wire

We can see oil discoloring the ocean, blackening coastlines and covering wildlife, but carbon dioxide is colorless and odorless.

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Despite occasional growls about unnamed enemies blackening the army's name, General Basbug seems quietly to be co-operating with the government in its investigation.

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This included a blackout across significant portions of the Worldwide Web, with Wikipedia going dark and Google blackening its logo.

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Blackening copper allows it to absorb more light and heat, increasing the range of uses for the metal.

BBC: Copper wire

Doorstep lending, or home credit as it is termed by the trade, is a counter-cyclical business: in a downturn, bad debts pile up, blackening credit histories.

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