Verified gold - afterwards, it acted differently (13)
I believe the answer is:
authenticated
'verified' is the definition.
(thesaurus)
'gold afterwards it acted differently' is the wordplay.
'gold' becomes 'Au' (Au is the chemical symbol for gold).
'afterwards' becomes 'then' (I've seen this before).
'differently' is an anagram indicator.
'it'+'acted'='itacted'
'itacted' is an anagram of 'ticated'.
'au'+'then'+'ticated'='AUTHENTICATED'
(Other definitions for authenticated that I've seen before include "proved to be genuine" , "Validated" , "Established as genuine" , "Certified" , "Shown to be true" .)