Staining damage linked with expensive jewellery (8)
I believe the answer is:
marbling
'staining' is the definition.
(marbling is a kind of staining)
'damage linked with expensive jewellery' is the wordplay.
'damage' becomes 'mar' (to mar is to spoil or damage).
'linked with' says to put letters next to each other.
'expensive jewellery' becomes 'bling' (informal term for jewellery. I am not sure about the 'expensive' bit.).
'mar'+'bling'='MARBLING'
Can you help me to learn more?
(Other definitions for marbling that I've seen before include "Streaky lines" , "Distribution of fat" , "Mottled effect" .)