Unusual lustre is outcome (6)
I believe the answer is:
result
'is outcome' is the definition.
(I've seen this in another clue)
'unusual lustre' is the wordplay.
'unusual' is an anagram indicator.
'lustre' is an anagram of 'RESULT'.
(Other definitions for result that I've seen before include "Consequence in Ulster (6)" , "Verdict" , "'Outcome, consequence (6)'" , "'Outcome, upshot (6)'" , "End - issue" .)