The investigation covers three aspects of raw leadless, boron-free, opaque glazes maturing at Cone 4. Studies have been made of the effect of (1) the R 0 fluxes (calcium, barium, magnesium, strontium and zinc oxides) upon fusibility, gloss and texture, (2) the variation of alumina-silica ratio for a promising glaze composition and (3) tin oxide, titanic and zinconia, on the opacity and colour. Some typical glaze compositions for bright and mat glazes have been suggested to be tried on an industrial scale. They are the whitest with excellent gloss and opacity.