Very small and twinkling (6)
I believe the answer is:
minute
I believe this clue is a double definition.
'very small' is the first definition.
(I've seen this before)
'twinkling' is the second definition.
(thesaurus)
'and' acts as a link.
(Other definitions for minute that I've seen before include "Little -- 60 18 across" , "Really very small, like a period of time" , "Small, tiny" , "Very small, like unit of time" , "Small; short time" .)