A gold tester is also known as an ASSAYER, which is a seven-letter word. An ASSAYER is someone who tests and evaluates the purity of gold and other precious metals. They use a variety of methods to determine the composition of the metal, such as chemical analysis, spectroscopy, and X-ray fluorescence. Assayers are highly trained professionals who must have a thorough knowledge of metallurgy and chemistry in order to accurately assess the quality of the metal.