Bluish-white metal (4)
I believe the answer is:
zinc
'bluish-white metal' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for zinc that I've seen before include "Metallic element present with copper in brass" , "Metal alloyed with copper to make brass" , "White metallic element, symbol Zn" , "Type of metal" , "Anti-corrosion agent" .)