Egyptian blue, the world's oldest synthetic pigment, has been recreated.

▲ A vessel containing Egyptian blue, the world's oldest synthetic pigment, is on display at the Carnegie Museum of Natural History in the United States. Photo: Europa Press

Europa Press

La Jornada Newspaper, Thursday, June 5, 2025, p. 6

Madrid. Researchers at Washington State University (WSU) have recreated the world's oldest synthetic pigment, called Egyptian blue, used in ancient Egypt 5,000 years ago.

In a report published in the journal Heritage Science , the researchers note that they used a variety of raw materials and heating times to develop 12 pigment recipes, providing useful information for archaeologists and conservation scientists studying ancient Egyptian materials. The work was conducted in collaboration with the Carnegie Museum of Natural History and the Smithsonian's Museum Conservation Institute.

Expensive minerals

We hope this is a good case study of what science can contribute to the study of our past , said John McCloy, first author on the paper and director of the WSU School of Mechanical and Materials Engineering. The goal of this work is to highlight how modern science reveals hidden stories in ancient Egyptian artifacts .

Although Egyptian blue pigment was valuable in ancient times, there is little archaeological evidence of its production. It was used as a substitute for expensive minerals such as turquoise and lapis lazuli and was used to paint wood, stone, and a papier-mâché-like material called cartonnage. Depending on its ingredients and processing time, its color ranges from deep blue to dull gray or green.

After the Egyptians, the pigment was used by the Romans, but by the Renaissance, knowledge of its manufacture had been largely forgotten.

In recent years, interest in the pigment has resurfaced due to its interesting optical, magnetic, and biological properties, with potential new technological applications, McCloy said.

The pigment emits light in the near-infrared part of the electromagnetic spectrum, invisible to humans, meaning it could be used for tasks such as fingerprinting and creating counterfeit-proof inks. Furthermore, its chemical composition is similar to that of high-temperature superconductors.

It started out as a fun project, as we were asked to produce some materials to display at the museum, but there's a lot of interest in it , said McCloy, who, in addition to being a professor of materials science and engineering, has a master's degree in anthropology.

To understand its composition, researchers, including a mineralogist and an Egyptologist, created 12 different pigment recipes from mixtures of silicon dioxide, copper, calcium, and sodium carbonate. They heated the material to 1,000 degrees Celsius for between one and 11 hours to replicate the temperatures that would have been available to ancient artists.

After cooling the samples at different speeds, they studied the pigments using modern microscopy and analysis techniques never before used for this type of research, comparing them with two ancient Egyptian artifacts.

Very heterogeneous

Egyptian blue included a variety of blue colors, depending on its place of manufacture and quality. Researchers discovered that the pigment is very heterogeneous.

There were people who were making the pigment and then transporting it, and the final use was somewhere else , McCloy said. One of the things we observed was that even with small differences in the process, the results were very different .

The researchers found that, in fact, only about 50 percent of the blue components are required to obtain the bluest color.

It doesn't matter what the rest is, which was quite surprising to us , McCloy noted. You can see that each pigment particle contains a huge number of elements; it's not uniform at all .

The resulting specimens are currently on display at the Carnegie Museum of Natural History in Pittsburgh, Pennsylvania, and will be part of the museum's new long-term gallery dedicated to ancient Egypt.

AFP

La Jornada Newspaper, Thursday, June 5, 2025, p. 6

Toulouse. Fossilized jaw fragments from two-million-year-old infants found in Africa, the cradle of humanity, have helped a Franco-Italian research team shed new light on the origins of the human race.

The study, conducted by José Braga (French National Center for Scientific Research, CNRS-University of Toulouse) and Jacopo Moggi-Cecchi (University of Florence) and published in Nature Communications , shows greater diversity and complexity than expected at the beginning of the Homo genus.

The bones on which this research is based (two mandibles and a maxilla from babies exhumed a few years ago in Ethiopia and South Africa) show that from that moment in the individual's life, 2.2 million years ago, we were dealing with two distinct species that developed in completely different ways , Braga said.

Morphological differences

While the jawbone from Ethiopia's lower Omo Valley, attributed to Homo habilis , is very different from that of modern human children , the one from the South African site of Kromdraai, attributed to Homo erectus , is very close to that of modern human children , he said.

Due to the young age of the individuals to whom they belonged, it seems unlikely that the morphological differences so marked are due to the environment (lifestyle or diet), as may be the case with the skeletons of adults.

The comparison of both jaws shows us that, for millions of years, they were two completely different species that coexisted somewhere on the African continent , and that Homo erectus was closer to us than Homo habilis , he added.

“These new discoveries contribute to a more nuanced view of the origins of the genus Homo ,” when the first representatives of the human lineage diverged from the other great apes.

This suggests that the roots of humanity are both older, more diverse and more branched than previously thought , the CNRS noted.