To discover the quantity of metal in a small piece of ore is called assaying. Assaying, therefore, means the estimation of one or more metals in an ore or alloy.

What does the word Assayers mean?

a person or company that tests a metal, etc. to find out how pure it is: the chief assayer at the Birmingham Assay Office.

What is the plural of assay?

/ˈæˌseɪ/ noun, plural assays [count]