Unusual garnets recollected (7)
I believe the answer is:
strange
'unusual' is the definition.
(I know that unusual can be written as strange)
'garnets recollected' is the wordplay.
'recollected' is an anagram indicator (letters recollected and rearranged).
'garnets' anagrammed gives 'STRANGE'.
(Other definitions for strange that I've seen before include "Out of the ordinary" , "Unusual, surprising" , "Extraordinary" , "Odd, peculiar" , "Queer" .)