The colour of ceramics from Bell Beaker contexts in NW Spain: relation to elemental composition and mineralogy

In this paper we characterise the mineralogical and elemental composition and the colour (CIELab space) of Bronze Age pottery sherds from NW Spain, using X-Ray diffraction, X-Ray fluorescence and reflectance spectroscopy, respectively. For half of the samples we also determined the content in secondary iron oxi-hydroxides (sFe, iron extracted with dithionite–citrate), using atomic absorption. The aim of the investigation was to study the relationship between the colour and the elemental and mineralogical composition, and to explore the intentionality of the resulting colour. Samples had a low luminosity and were located in the quadrant of the CIELab space ranging from red to yellow (hab: 0–90°), showing low hue variability but a wider range of variation in chromaticity. In terms of composition they showed a large mineralogical (12 different minerals were identified) and chemical (from acidic/felsic to basic-ultrabasic/mafic compositions) variation.