A precious metal testing apparatus and methods adapted to analyze impurities in a precious metal test sample is described. The testing apparatus contains a test probe that has a replaceable portion and that is connected to a meter to measure resistance. The replaceable portion contains or forms a reservoir that includes at least one electrolyte component, a conductive member, and a fibrous tip. The electrolyte component is fluidly associated with a fiber tip and the conductive member contacts an electrical contact located outside the reservoir. Methods of testing and instructions regarding such methods are also included.