Evaluate for purity (5)
I believe the answer is:
assay
(Other definitions for assay that I've seen before include "Test, or say, to establish quality" , "Evaluate" , "Test, check" , "Test ore for value" , "Put to the proof" .)
I believe the answer is:
assay
(Other definitions for assay that I've seen before include "Test, or say, to establish quality" , "Evaluate" , "Test, check" , "Test ore for value" , "Put to the proof" .)