ABSTRACT
When visually examining the explosive sample with the stereomicroscope, the physical characteristics of the explosive are noted, including, but not limited to, particle size and dimensions, size distribution, shape, color, similarity in appearance among different particles, surface roughness/ coating, and porosity. Multiple particles of the explosive should be analyzed and the characteristics of the unknown explosive can then be compared to known exemplars to presumptively determine the identity of the explosive. In addition to microscopic examination, a physical examination of the questioned explosive may also include an ignition susceptibility test. The purpose of the test is to examine physical characteristics of an explosive through its reaction of combustion when exposed to an open ame. The test is conducted by exposing a single particle of the explosive to an open ame and observing the combustion reaction of the explosive. Observations of the combustion include ame color, how energetic the ame is, amount and color of smoke produced, sounds produced, other smells, color of residue, and amount of residue remaining. Like the microscopic examination, the observations of the explosive can then be compared to known explosive standards to assist in determining the identity of the unknown explosive.
