How Scientists Recreated Egyptian Blue: The World’s Oldest Known Synthetic Pigment!
A team of researchers from Washington State University (WSU), working alongside experts at the Carnegie Museum of Natural History and the Smithsonian’s Museum Conservation Institute, has successfully recreated the world’s oldest known synthetic pigment - Egyptian blue. In doing so, they’ve shed new light on the remarkable craftsmanship of ancient Egypt.
In a study recently published in NPJ Heritage Science, the researchers detailed how they developed a dozen authentic methods for making Egyptian blue, a vivid pigment that dates back to around 3100 BCE. Originally crafted as a more accessible alternative to costly gemstones like lapis lazuli and turquoise, Egyptian blue was widely used in ancient Egypt to decorate sculptures, tombs, coffins, murals and other ceremonial objects. While its use faded during the Roman era and all but disappeared by the Renaissance, its significance has endured.
To replicate the pigment, the team mixed materials that ancient artisans likely had to hand—silicon dioxide, copper, calcium, and sodium carbonate. These ingredients were then fired at around 1,000°C, mimicking the limits of ancient kilns. Heating times varied from one to eleven hours, and the researchers experimented with different cooling rates. Interestingly, they found that slower cooling produced a deeper, more vibrant blue.
Photo Credit: Matt Unger, Carnegie Museum of Natural History
One of the study’s most unexpected findings was that the striking blue shade didn’t require a pigment made entirely of cuprorivaite, the blue crystal long thought to be key to Egyptian blue. Instead, they discovered that a mixture containing only about 50% of the blue-coloured material could achieve the desired tone.
Close analysis using tools such as X-ray diffraction and infrared photoluminescence mapping revealed that Egyptian blue isn’t a uniform substance, but rather a complex composite. Each grain contained a mix of cuprorivaite, silica glass, wollastonite, and at times, copper oxide. This structural diversity contributes to the pigment’s colour variations depending on how it’s made and applied.
The research also showed how important cooling methods were. Samples allowed to cool slowly, possibly by being buried in sand or ash, contained up to 70% more cuprorivaite than those cooled quickly in air. The result? Richer, more intense blues.
Beyond its historical intrigue, Egyptian blue is gaining attention in modern science. When exposed to visible light, it emits infrared radiation, which is invisible to the naked eye but valuable for applications such as security printing, biomedical imaging, and telecommunications. Its crystal structure is also similar to materials used in high-temperature superconductors, offering exciting potential for future materials research.
Although the project began as a way to create replicas for museum displays, it evolved into a deeper exploration of ancient innovation and its lasting relevance today. Visitors can now see the recreated pigment samples on display at the Carnegie Museum of Natural History in Pittsburgh, as part of a new exhibition on ancient Egypt.