Raman spectroscopic study of 3000-year-old human skeletal remains from a sambaqui, Santa Catarina, Brazil

A Raman spectroscopic study of red-pigmented human bones from a 3000-year-old sambaqui burial was undertaken for the first time. Visible (633 nm) and near-infrared (1064 nm) excitation were used to characterize the pigment and its substrate; the red pigment is haematite, iron(III) oxide, which proved to be of a pure form and for which no previous heat treatment processing had been adopted. There is clear evidence in heavily pigmented areas of a 'limewash' layer which had been applied to the body of the deceased prior to treatment with ochre. Comparisons made with previous Raman studies of archaeological bone from a separate excavation indicate that mineralization of the present specimens is well advanced, with evidence of calcium carbonate incorporation into the hydroxyapatite phosphatic matrix.