Determination of Unique Fracture Patterns in Glass and Glassy Polymers, which features a study on the determination of unique fracture patterns in glass, tested the hypothesis that fracture patterns in glass and glassy polymers are unique and, therefore, unlikely to be reproducible due to distinctive matrix imperfections. The study indicated that although some similarities were found in a limited number of specific fracture lines, the overall patterns were not duplicated. The fracture patterns of plastic lenses exhibited some general similarities. In many of the lenses, the centers completely broke out, or they fractured along the mold lines of the lens. There were no duplicates of overall fracture patterns. The report recommends using caution when evaluating the uniqueness of fractures in this type of material. This research aids in substantiating court testimony about the significance of fracture matching of broken glass and polymers. For additional information on this study, go to www.ncjrs.gov/App/Publications/abstract.aspx?ID=263535, NCJ 241445.