Precious stones left in fruit (6)
I believe the answer is:
pearls
'precious stones' is the definition.
(pearl is a kind of precious stone)
'left in fruit' is the wordplay.
I cannot really understand how this works, but
'left' could be 'l' (common abbreviation) and 'l' is found within the answer.
'fruit' could be 'pea' (pea is a kind of fruit) and 'pea' is found within the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for pearls that I've seen before include "Gemstones produced by molluscs" , "Jewels from bi-valves" , "types" , "Nacreous gems" , "Precious particles in shellfish" .)