It's of great value in management (3)

I believe the answer is:

gem

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

'it's of great value' is the definition.
I can't judge whether this defines the answer.

'in management' is the wordplay.
'in' indicates a hidden word.
'GEM' is hidden within 'management'.

Can you help me to learn more?

(Other definitions for gem that I've seen before include "Pleasant and cheerful (from German)" , "one of the Cairngorms?" , "Pearl" , "perfect specimen" , "A jewel of an Orangeman" .)

I've seen this clue in the Evening Standard.

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