Possibly copper’s sphere of operation (7)

I believe the answer is:

element

This clue is a double definition.

'possibly copper's' is the first definition.
(copper is a chemical element)

'sphere of operation' is the second definition.

(Other definitions for element that I've seen before include "of the weather" , "silver perhaps?" , "An abstract part of something" , "fire, perhaps, once" , "Constituent -- habitat" .)

I've seen this clue in The Times and The Sun.

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