Potentially of interest to someone … here’s the abstract (the article itself is payfer, of course):
Powdered pigments found in bowls from the Pompeii archaeological site and some wall-painting fragments from the Vesuvian area (conserved in the National Archaeological Museum of Naples) were investigated by microscopic Raman and FTIR spectroscopies, X-ray diffraction and scanning electron microscopy-energy dispersive X-ray. Brown, red and yellow pigments are common ochres based on goethite and haematite. The blue pigment is Egyptian blue: the presence of tridymite and cristobalite indicates firing temperatures in the 1000-1100 °C range. Pink pigments were prepared both with purely inorganic materials, by mixing haematite and Egyptian blue (violet hue), or presumably by adding an organic dye to an aluminium-silica matrix. A white powder found in a bowl is composed mainly of the unusual pigment huntite (CaMg3(CO3)4). Celadonite is found in the green samples from the wall paintings, together with Egyptian blue and basic lead carbonate, while the heterogeneous green pigment in a bowl shows malachite mixed with goethite, Egyptian blue, haematite, carbon, cerussite and quartz.
- via Pigments used in Roman wall paintings in the Vesuvian area. Irene Aliatis. 2010; Journal of Raman Spectroscopy.
There’s a somewhat longer summary at Volcanic spectroscopy (not sure how that’s affiliated with the journal)