Dr. John McCloy, Washington State University

We recreated Egyptian blue (used in Egypt from the fourth millennium BC through the Roman period) to uncover the science behind its color, ranging from gray or green to deep blue. We produced 12 versions of Egyptian blue and compared them with artifacts, using advanced X-ray techniques, spectroscopy, and quantitative color measurements. We found Egyptian blue is a complex mixture of phases, with hue controlled by particle size, glass content, and cuprorivaite–silica ratios. Even small changes in materials or heating could dramatically shift its color.

These findings reveal ancient craftspeople as skilled materials scientists. Beyond cultural insights and conservation, Egyptian blue’s infrared glow continues to inspire modern technologies,
linking past creativity with future innovation.