The origin of black pigmentation in a sample of Mexican prehispanic human bones

The study of black patches and spots in prehispanic bones of Tlatelolco and Tlapacoya is presented. The chosen characterization techniques, X-ray Fluorescence, X-ray Diffraction, Scanning Electron Microscopy, Energy Dispersive X-ray Spectroscopy, Infrared Spectroscopy and Gas Chromatography are complementary and they all conclude that the bone black pigment is constituted, mainly, by amorphous carbon and some mineral inclusions. Gas Chromatography and Infrared Spectroscopy show that the pigment is constituted by organic compounds as aromatic hydrocarbons, mainly bitumen. An explanation on how the spots were formed is proposed.

► We report on black stains in Tlatelolco and Tlapacoya (Two cultures, two epochs).
► The black pigmentation is found mainly in the articulations.
► The black spots and stains are shown to be petroleum derivatives.
► They are due to the use of tools to dismember bodies.