Relationship between Colours of Ochre from Roussillon and Content of Iron-Bearing Minerals

TL;DR

This study investigates the relationship between ochre color from Roussillon and its mineral content using Mossbauer spectroscopy and colorimetry, revealing how iron minerals influence ochre coloration.

Contribution

It combines mineralogical analysis with color measurement to elucidate the link between iron-bearing minerals and ochre color, providing a comprehensive understanding of their relationship.

Findings

Both a* and b* color coordinates are responsible for ochre color.

Iron mineral content correlates with specific colorimetric values.

Quantitative mineral analysis links mineral phases to color variations.

Abstract

Nine samples of ochre originating from the Sentier des Ocres near Roussillon, France, were studied with Mossbauer spectroscopy and Spectro-photo-colorimetry. The former yielded a quantitative phase analysis of iron containing minerals (goethite, hematite and kaolin), and the latter enabled determination of the CIE-L*a*b* colorimetric coefficients. Based on the results obtained it is shown that both a* and b* coordinates are responsible for the colour of the investigated ochres.