Fourier-transform infrared spectroscopic characterization of naturally occurring glassy fulgurites

We report here for the first time the spectroscopic characterization of natural fulgurites of Garuamukh. On April 22, 2005 at 04:00 local time, large amounts of black-brown colour of colloidal solution came out from below the earth’s surface at Garuamukh near Nagaon town (latitude 26°20′39″N, longitude 92°41′39″E, Assam, India) with fire and smoke. This colloidal solution got transformed into fulgurites, glassy material, within a few hours. We present here the characterization of the fulgurites by Fourier transform infrared (FTIR) absorption, X-ray diffraction and X-ray fluorescence methods. The amorphous nature of the substance has been confirmed by Fourier transform infrared spectra of the fulgurites, which exhibit prominent absorption band in the region 400–1200 cm −1 , the basic component of amorphous silica. The present study might have significant implications in understanding the thermodynamic properties of naturally occurring glasses, which are formed by shock metamorphism.