A NOVEL METHOD OF DEVELOPMENT OF THE LATENT FINGERPRINTS BASED ON THE POROSITY OF SILICEOUS ROCK POWDER CONTAINING FELDSPAR, BIOTITE AND ALBITE

Abstract

Background: Since ancient history, rock powder has been used in the commission of crime due to their widespread availability. The general sensation, even in the professional fingerprint area is that rock powder does not yield identifiable latent fingerprints. The author of this research paper selects some rocks of siliceous origin (SiO2).The siliceous rock powders have different process of formation and internal texture. Their mechanical adhesion, porosity and lustrous properties help to develop latent fingerprints. However, the rock powders could be obtained abundantly from the rocks exposed in natural sources containing fine grain of quartz (SiO2), K-feldspar, biotite, muscovite, and flaky minerals. The particle size of rock powders is obtained as fine dust of -100 to -120 mesh size. Result: The small particle size results in easy adherence to the oily components of the perspiration of the latent fingerprints. Developed fingerprints have demonstrated better appearance on some contrast surfaces than bright surfaces. In the present study, rock powder of dolerite and granite gneiss of the igneous clans and phyllite and quartzite of the metamorphic clan (high content of silicate minerals) demonstrated best results. However, rock powders of sedimentary origin such as glauconite sandstone have not produced any good result. Conclusion: Based on previous applications in forensic science, few siliceous powders were used for the identification of invisible fingerprints from the crime scene. Also, these are less toxic as compared to metallic powders, eco-friendly (obtained from the natural source as compared to the synthetic powders of chemical origin) and easily available in nature in abundance. The processing cost is very low in preparing it and is economically cheap to meet the requirement of a forensic expert. The rock powders from selected rock can be a good substitute for fingerprint developing powder in being comparatively cheaper than other commercially available powders. © 2022, Medico Legal Society. All rights reserved.