Egyptians created the first blue pigment about 5,000 years ago. They used the pigment in paints to decorate coffins, murals, and more. The pigment was mostly composed of chemical elements like copper and calcium as well as chemical compounds like silica sand. But the exact recipe for how the pigment was made was lost to time—until now.
Researchers at Washington State University tested 12 different pigment recipes, baking them at 1,000 degrees Celsius for between 1 and 11 hours. No matter the recipe, cooling the pigment slowly over time produced the brightest blue. “The fact that it is so challenging to reliably reproduce it even today speaks to the extreme talent of our ancestors in antiquity,” says John Stuart McCloy, lead researcher of the study.