A simple rapid fusion technique, in which lithium metaborate is used as the fluxing medium, has been developed for the analysis of mineral silicates, coal ash, furnace deposits and other related materials. A single fusion, followed by dissolution in dilute nitric acid, allows the major constituents of the samples to be determined by atomic-absorption spectrophotometry within the following ranges: SiO2 5 to 80 per cent., Al2O3 2 to 60 per cent., TiO2 0·5 to 5 per cent., Fe2O3 2 to 60 per cent., CaO 1 to 40 per cent., MgO 1 to 40 per cent., Na2O 0·5 to 20 per cent. and K2O 0·1 to 10 per cent., with a precision comparable with that of conventional methods used for silicate analysis.