Contribution to the Study of Heavy Minerals In Forensic Soil Investigations.

The heavy mineral fraction can be of considerable value in forensic soil studies. The role of these minor accessory minerals ranges from their application in routine forensic soil comparisons to their special value as indicators of geological provenance when attempting to discover the location from which unknown dust or soil evidence originated. The recovery, concentration, identification and interpretation of heavy mineral suites requires special consideration in forensic examinations since the amount of sediment available for these analyses is typically orders of magnitude less than that available to a sedimentologist. The limited quantity of grains available for study in these situations necessitates the use of special techniques for their isolation and identification. The small number and size of the grains also requires the application of different criteria for interpretation than those used in more routine heavy mineral analyses. This presentation focus on four aspects of this topic: * The special technique for isolating and analyzing heavy minerals from casework sized evidence samples. * The difficulties in quantitation and the recognition and importance of varietal differences as they apply to interpretation. * Reference materials required for interpretation of results from comparative investigations and in the development of investigative leads. * Selected casework examples.