what is assaying
DEFINITION of 'Assay'. The process of analyzing a physical sample to determine its composition. In financial markets, the term assay usually refers to the chemical analysis of a mineral or ore sample to ascertain its content of precious metals or minerals, such as gold, copper, or uranium.he process of analyzing a physical sample to determine its composition. In financial markets, the term assay usually refers to the chemical analysis of a mineral or ore sample to ascertain its content of precious metals or minerals, such as gold, copper, or uranium.