It's coal maybe but quite indifferent (7)
I believe the answer is:
stoical
'quite indifferent' is the definition.
'stoical' can be an answer for 'indifferent' (thesaurus). I'm not sure about the 'quite' bit.
'it's coal maybe' is the wordplay.
'maybe' indicates anagramming the letters.
'its'+'coal'='itscoal'
'itscoal' with letters rearranged gives 'STOICAL'.
'but' is the link.
Can you help me to learn more?
(Other definitions for stoical that I've seen before include "Impassive" , "patient, > uncomplaining" , "able to endure suffering" , "Seeming to be unaffected by pleasure or pain" , "Showing endurance" .)