Two green layers from Roman mural paintings from Lero (Alpes maritimes, France) were studied by means of x-ray diffraction, electron microprobe, X-ray energy dispersive microanalysis and scanning electron microprobe. The paint layer is coloured with a crushed clay, the glaucony, to which 3% in weight of crushed aegyptian blue has been added. Various types of inclusions were characterized and the chemical composition of the glauconies approached.