Analysis of gunshot residue (GSR). Displays of the results of GSR analysis with a scanning electron microscope (SEM, centre) & an X-ray beam (right). GSR is formed when firing a gun. Various materials are used in the explosive mix that fires a bullet, and these are ejected from the gun in a cloud of tiny GSR particles. They are deposited on the hand and clothes of the person who fired the gun. An adhesive GSR stub is used to sample suspects for analysis. SEM analysis (GSR particle shown) shows surface details that can be compared with known GSR samples. X-ray beam energy dispersive analysis (EDA or EDX) reveals the presence of the lead, barium and antimony that is found in GSR.