In one's element here! (6)

I believe the answer is:

indium

I'm a little stuck... Click here to teach me more about this clue!

'in one's element' is the definition.
'indium' can be an answer for 'element' (indium is a kind of element). I am not certain of the 'in one's' bit.

I don't understand the remainder of the clue.

Can you help me to learn more?

(Other definitions for indium that I've seen before include "Metallic element, In" , "Silvery-white metal" .)

I've seen this clue in The Guardian.

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