NCJ Number
218651
Date Published
January 2005
Length
4 pages
Annotation
The Scientific Working Group for Materials Analysis presents guidelines for assessing fracture features as part of forensic glass analysis.
Abstract
The guidelines focus on the characterization and assessment of the significance of fracture features in glass as observed through microscopic and macroscopic examination. The reconstruction of broken glass objects is also addressed. An introductory discussion of the significance and use of the analysis of glass fractures notes that fracture patterns are unique. They reveal the nature of the glass and the travel direction, speed of the object that fractured the glass, and the sequence of multiple impacts. Regarding sample handling, extreme care should be taken in order to prevent further breakage of the glass during packing, shipping, or unpacking. Although guidelines for sample handling are discussed in another report (see NCJ-218649), the current report notes that proper sample preparation and technique are prerequisites for obtaining reliable results in analyzing fracture patterns. Guidelines for the analysis of glass fractures address physical reconstruction and types of fractures. Guidelines for analyzing types of fractures focus on fractures caused by low velocity impact, high-velocity impact, and a high temperature. Regarding the reuniting of glass fragments, the guidelines advise that glass fragments with coinciding edges came from breakage caused by the same object. If the direction of impact and/or the sequence of impact have been determined, they should be reported. 2 references and a 12-item bibliography