Valuable bit of information (6)
I believe the answer is:
nugget
'valuable bit of information' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for nugget that I've seen before include "valuable bit of information" , "valuable piece of information" , "Scrap of information" , "Solid lump of a precious metal" , "Lump of metal like gold" .)