Crest in a kind of black colour (9)
I believe the answer is:
cochineal
'colour' is the definition.
(I have seen 'Red colour' mean 'cochineal' so perhaps 'colour' could also mean 'cochineal')
'crest in a kind of black' is the wordplay.
'crest' becomes 'chine' (I can't justify this - if you can you should believe this answer much more).
'in' means one lot of letters goes inside another.
'a kind of black' becomes 'coal' (I've seen this in another clue).
'chine' put into 'coal' is 'COCHINEAL'.
Can you help me to learn more?
(Other definitions for cochineal that I've seen before include "Red food dye (from beetles)" , "Crimson dye from crushed insects" , "Red colour" , "Scarlet food dye" , "Red food colouring" .)