Sheet or Container?—Forensic Glass Comparisons with an Emphasis on Source Classification

The value of source-type classification for small fragments of glass encountered in trace evidence casework is restressed. The incorporation of classification techniques into the classical refractive index/density comparison scheme is described. The techniques employed are applications of those developed by the British forensic science community over the past 5 years, targeted at differentiating the 2 most common end-use types of soda-lime-silicate glasses encountered in casework—sheet glass and container glass. The results of method verification studies on 30 window glass specimens for tempered/nontempered classification and on 140 window and container glass specimens for sheet/container classification are reported. Although some limitations were revealed with the domestic samples used, the overall success of the approach was established.