Colour of pure damask (3)
I believe the answer is:
red
'colour' is the definition.
(red is a kind of colour)
'of pure damask' is the wordplay.
'of' indicates the answer is hidden within the clue.
'RED' is hidden in the letters of 'pure damask'.
(Other definitions for red that I've seen before include "Florid" , "Glowing" , "Colour of Merlot wine" , "Flushed" , "Crimson" .)