Joyce's "Green Gem of the Silver Sea” (4)
I believe the answer is:
erin
'joyce's green gem of the silver sea' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for erin that I've seen before include "Another name for 11 ac" , "'Come back to ...' (emigrant song)" , "Romantic, archaic name for Ireland" , "Early and poetic name here" , "Ireland (poet.)" .)