Naturally occurring minerals or their synthetic analogues have been important as pigments used in artistic and cosmetic contexts in global antiquity. The analysis and identification of mineral pigments, though routine to the petrologist or mineralogist, also requires specialist knowledge of the archaeological contexts and available technologies and trade. This paper attempts to present an analytical approach to the study of mineral pigments in archaeology and also introduces the range of mineral pigments encountered in works of art and painted objects on archaeological sites and in museums. It attempts to cover the range of mineral and synthetic inorganic pigments used in global cultures from to the early Medieval period.

The realization that the addition of volcaniclastic material to hydrated lime cements produced a concrete that was not only waterproof but would also set under water revolutionized the building programmes of the Roman Empire. The material became known as pulvis Puteolis (dust of Puteoli) from the Latin name for modern Pozzuoli on the Bay of Naples. Pozzuoli itself is the root of ‘pozzolana’, meaning any material (in most natural cases, volcanic in origin) that is capable of producing a hydraulic (waterproof) set when combined with lime cement. A reaction between quicklime (CaO) and volcanic ash promotes the growth of phases that, rather than reverting to calcium carbonate on curing, as in non-hydraulic cements, produce a hard, watertight material. Although volcanic materials were the aggregates of choice in the building projects of Imperial Rome, being locally derived, abundant and relatively easily quarried, their hydraulic properties were soon fully realized, perhaps as a result of observations of naturally calcite-cemented scoria and ash flows in sea water or from experimental building. Away from the Imperial centre, terrestrial architecture involving waterproofing (baths and cisterns) effectively used waste ceramic sherds as a substitute for volcanic ash. However, for marine and riparian architecture, volcanically derived pozzolanic cements were the preferred material of use.

Pigments from paint palettes and a grindstone excavated from the pharaonic town of Amara West (c. 1300–1050 BCE), which lies between the Second and Third Cataracts of the Nile, were examined using polarized light microscopy, attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), X-ray diffraction, and scanning electron microscopy with energy dispersive X-ray spectroscopy. Most of the pigments were consistent with the typical ancient Egyptian palette, but the greens and some blues were unusual. Two types of green pigment were identified, chlorite (varieties clinochlore and penninite) and copper chloride hydroxide (atacamite type). The former constitutes a type of green earth which has only rarely been identified in pharaonic Egyptian contexts and may be more widespread than is currently reported. The majority of the blue pigment samples were Egyptian blue, but some were found to be a blue earth, the main component of which being sodic amphibole riebeckite. The use of this mineral as a pigment has not previously been reported in any Nile Valley context. These results prompt questions around local and potentially indigenous practices within an ancient colonial context, and highlight avenues for future research.