Pink and black stuff? That's about right (5)
I believe the answer is:
coral
'pink' is the definition.
(coral is a shade of pink)
'black stuff? that's about right' is the wordplay.
'black stuff?' becomes 'coal'.
'that's about' indicates putting letters inside.
'right' becomes 'r' (common abbreviation).
'coal' enclosing 'r' is 'CORAL'.
'and' acts as a link.
(Other definitions for coral that I've seen before include "Material of many Pacific islands." , "Marine polyps, often forms reefs" , "It forms reefs, generally in warm seas" , "Reef material" , "marine life form" .)