They guard treasures, yet possess no gems (6)
I believe the answer is:
gnomes
'they' is the definition.
Both the answer and definition are plural nouns.
Maybe there's an association between them I don't understand?
'guard treasures yet possess no gems' is the wordplay.
'no gems' anagrams to 'GNOMES'.
However, I'm unsure how the anagram is indicated.
Can you help me to learn more?
(Other definitions for gnomes that I've seen before include "Ornamental garden figures" , "Legendary little figures, in the garden perhaps" , "Legendary creatures" , "Garden dwarfs from Zurich?" , "Zurich goblins" .)