Odd arrangement of garnets (7)
I believe the answer is:
strange
'odd' is the definition.
(I've seen this in another clue)
'arrangement of garnets' is the wordplay.
'arrangement of' indicates anagramming the letters.
'garnets' is an anagram of 'STRANGE'.
(Other definitions for strange that I've seen before include "Different" , "Odd or unfamiliar" , "Unknown or peculiar" , "- - Fruit (song)" , "Offbeat" .)