Things Assayers Assay is a job description for a person who tests and evaluates ore samples to determine their composition and quality. An Assayer is responsible for analyzing the chemical composition of ores, which are naturally occurring rocks that contain valuable minerals. Ores are typically mined from the earth and then processed to extract the valuable minerals. Assayers use a variety of techniques to analyze the ore samples, including spectroscopy, X-ray diffraction, and wet chemistry. The results of the analysis are used to determine the value of the ore and its suitability for further processing.