Pure sample of orange lichen (7)
I believe the answer is:
angelic
'pure' is the definition.
(I've seen this before)
'sample of orange lichen' is the wordplay.
'sample of' says the answer is hidden in the clue (an extract or sample of the clue).
'ANGELIC' is hidden within 'orange lichen'.
(Other definitions for angelic that I've seen before include "Heavenly - entrancing" , "Exceptionally innocent" , "Of innocent beauty" , "Very well behaved" , "Saint-like" .)