In the act of re-forming diamonds hardened (9)

I believe the answer is:

redhanded

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'in the act of re-forming diamonds hardened' is the definition.
I can't tell whether this defines the answer.

'forming diamonds hardened' is the wordplay.
'forming' indicates anagramming the letters.
'diamonds' becomes 'd' (abbreviation in card games).
'd'+'hardened'='dhardened'
'dhardened' is an anagram of 'REDHANDED'.

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I've seen this clue in The Times.

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