Figure 2.

Representative Raman spectrum (a) of quartz (Q), calcite (Cc) and hematite (He) and FEG-SEM images of a dust particle(b) and a diatom (c) recorded at 785 nm laser wavelength. When analyzed using EDS both (c and d) showed Si and O peaks in the spectra. Scales 2 and 1 μm respectively.