Spice in stone cask brought up (6)
I believe the answer is:
nutmeg
'spice' is the definition.
(I know that nutmeg is a spice)
'stone cask brought up' is the wordplay.
'stone' becomes 'gem' (I've seen this before).
'cask' becomes 'tun' (tun is a kind of cask).
'brought up' shows that the letters should be reversed in order (in a down clue, letters go up).
'gem'+'tun'='gemtun'
'gemtun' reversed gives 'NUTMEG'.
'in' acts as a link.
(Other definitions for nutmeg that I've seen before include "Aromatic seed - tropical tree" , "(In soccer) kick the ball between an opponent's legs" , "Aromatic spicy kernel" , "Hard fruit and girl for a spice" , "Give out light" .)