A black depositional layer on the inner surface of a Neolithic carinated vessel from the archaeological site of Dikili Tash in Eastern Macedonia was examined scientifically. The layer was initially considered as decomposed organic matter and interest was focused on identifying the original organic contents. The scientific investigation, which included FTIR spectroscopy, analytical SEM examination and optical microscopy, revealed that the black substance was not organic but a pure iron oxide layer deposited on the vessel's inner surface, and reduced in places to black iron oxides, during a destructive fire. The conclusion is that this layer represents the remnants of the vessel's original content, which was a red hematite pigment. This unexpected find provides, for the first time, a missing link in the evidence of pigments used in Neolithic times, previously attested to only by finished products.