Material - South African metal? (5)
I believe the answer is:
satin
'material' is the definition.
(satin is a kind of material)
'south african metal?' is the wordplay.
'south african' becomes 'SA' (abbreviation).
'metal?' becomes 'tin' (tin is a kind of metal).
'sa'+'tin'='SATIN'
(Other definitions for satin that I've seen before include "Silky material" , "Fine material" , "Lustrous fabric" , "Silk fabric" , "Glossy textile" .)