Quantitative determination of water in granites by infra-red analysis

Two methods using nujol and hexachloro-butadiene mulls are described to analyse the water content of powdered granite samples. The nujol mull analyses were carried out on a Unicam SP Ioo spectrometer using the silica content of the rock as an internal standard. The hexachlorobutadiene mull analyses were done by a twin-path Unicam SP 2oo spectrometer, using hexachlorobutadiene as the internal standard. The broader and more pronounced V1 vibrational mode (345o cm-0 is ratioed to a standard of known composition. Comparisons are also made between absorption due to free water (V1 = 3450 cm-0 and combined water (V3 = 3680 cm-0 in aplites, biotite granite, and chlorite schists.