Small gem lettuce's beginning to bear fruit (5)
I believe the answer is:
pearl
'small gem' is the definition.
'pearl' can be an answer for 'gem' (pearl is a kind of gem). I'm unsure of the 'small' bit.
'lettuce's beginning to bear fruit' is the wordplay.
'beginning' says to take the initial letters.
'to' is a charade indicator (letters next to each other) (I've seen this in other clues).
'bear fruit' becomes 'pear' (I can't justify this - if you can you should believe this answer much more).
The first letter of 'lettuces' is 'l'.
'l' after 'pear' is 'PEARL'.
Can you help me to learn more?
(Other definitions for pearl that I've seen before include "Off-white colour" , "Lustrous structure in a mollusc shell" , "See 12" , "White - jewel" , "Object of great worth" .)