Test, as ore (5)
I believe the answer is:
assay
'test as ore' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for assay that I've seen before include "Check (a metal's) quality" , "Test of substance" , "Examine (ore or alloy?)" , "Analyse to find the properties" , "Test for metal content" .)