Various kinds of coloration were observed on a surface of metallic aluminium heated above its melting temperature under seven different atmospheres with different p(O2). Similar distributions of the coloration on a diagram of temperature (600-1400-degrees-C) and time (1-90 min) were found among these atmospheres. Yellowish colours (beige, gold, yellow, blonde, camel and sand) appeared over a fairly wide range of the diagram. From estimated thicknesses determined by weight increases and the order of appearance of the colours, it was concluded that the colour is caused by interference by the oxidized thin film produced on the smooth surface of the molten aluminium.