Characterization of manganese oxides and use of black pigments during the Paleolithic

Palaeolithic men used two main colors: red (natural hematite pure or mixed with clays) and black (charcoal or manganese oxides). These pigments could be prepared by grinding, mixing and perhaps heating. Physicochemical analyses attempt to determine the nature of the matter, its preparation mode and its provenance.<br />Different phases of manganese oxide are distinguished by their elemental composition, their structure and the oxidation state of Mn ion (II, III, IV). Structural transformation of manganese oxides during heat-treatment could be observed by means of TEM. Specific marks allow the distinction between natural or heat-treated manganese oxides, such as pores in bixbyite phase (Mn2O3).<br />Archaeological samples from various sites Palaeolithic in France and Spain were studied. From these analyses, new conclusions are drawn concerning the technical competence of prehistoric men. The samples from caves present both mixed and raw pigments. However black heated pigments have never been found in the studied samples.