Noah Webster's Dictionary (n.) One who assays. Specifically: One who examines metallic ores or compounds, for the purpose of determining the amount of any particular metal in the same, especially of gold or silver.

Multi-Version Concordance Assayer (1 Occurrence) Jeremiah 6:27 I have set thee among my people as an assayer, a fortress, that thou mayest know and try their way. (DBY NAS RSV)