Pale green gemstone (7)
I believe the answer is:
peridot
'pale green gemstone' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for peridot that I've seen before include "mineral" , "Gemstone -- pre-do it (anag)" , "Gem" , "Top ride (anag) - gemstone" , "olivine" .)