The School of Mechanical and Materials Engineering Seminar Series, “Egyptian Blue: Ancient Materials Engineering, Modern Functional Properties, and the Science of Color” Presented by Dr. John McCloy
About the event
Egyptian Blue: Ancient Materials Engineering, Modern Functional Properties, and the Science of Color
Presented by Dr. John McCloy, Director and Professor, School of Mechanical and Materials Engineering, Washington State University
Abstract:
Egyptian blue (EB) is humanity’s first synthetic pigment, developed over 5,000 years ago in ancient Egypt. EB represents an early triumph of materials engineering, combining controlled chemistry and thermal processing to achieve a durable and intensely colored material. The pigment is based on the chromophore cuprorivaite (CaCuSi₄O₁₀), a copper-containing silicate whose crystal-field-controlled electronic transitions produce its characteristic blue color and near-infrared luminescence (and is related to known Cu-based high temperature superconductors).
In this seminar, we examine EB from a modern materials perspective, linking processing, structure, and properties across length scales. Using controlled laboratory synthesis compared with characterization of ancient artifacts, we show that EB is not a single phase but a heterogeneous composite of cuprorivaite, silica polymorphs, and copper-bearing glass. Variations in raw materials, heat treatment, cooling rate, and particle size strongly influence phase development, microstructure, and resulting optical properties. Even modest changes in processing can shift the pigment from gray to green to deep blue, demonstrating a sensitivity of functional properties to processing.
Beyond its cultural and historical importance, EB exhibits current technologically relevant behavior including strong visible absorption, near-infrared emission (~910 nm), and stability arising from its layered copper-silicate framework. These properties have renewed interest in applications ranging from imaging and sensing to photonics and energy-related materials.
This talk highlights how ancient artisans effectively practiced materials engineering, observing property changes from changing raw materials, thermal treatment, and secondary processing. Insights from this earliest synthetic material continue to inform modern materials design and characterization, as well as providing a example to the public of the application of modern materials for forensic analysis.
Biography:
Dr. John S. McCloy is Professor and Director (Department Head) of the School of Mechanical & Materials Engineering and Lindholm Endowed Chair in Materials Engineering at Washington State University (WSU) and a joint appointee at Pacific Northwest National Laboratory (PNNL). His professional career includes academia (WSU, 12 y), national laboratory (PNNL, 5 y), and industry (Raytheon, etc., 10 y). At WSU, he leads the Nuclear, Optical, Magnetic, & Electronic (NOME) Materials Lab and the Crystals and SemiConductors (CASC) group, both within the Institute of Materials Research (IMR). These groups develop materials solutions for energy, environment, and security applications. Over his career, he has worked on diverse engineering problems, including cryogenics, composite structures, telescopes, optical ceramics, magnetic nanoparticles, ancient materials technologies, nuclear fuels, single crystal growth, and glass development for optics and immobilization of radioactive waste. He holds degrees in Materials Science & Engineering (MSE) from the Massachusetts Institute of Technology (BS) and the University of Arizona (MS, PhD), as well as an MA in Anthropology from Arizona. He is co-author of over 300 journal articles, book chapters, conference proceedings, public reports, and patents. He is a Fellow of the American Ceramic Society, a Fellow of SPIE the optics and photonics society, an elected member of the Washington State Academy of Sciences, and a Fulbright Scholar. In whatever spare time there is left, he enjoys reading, hiking, listening to music, studying foreign languages, traveling to visit ancient architecture, and playing board games with his family.