Standards

Long-Lost Pigment

WSU (MASK); SHUTTERSTOCK.COM (POWDER BACKGROUND)

ANCIENT COLOR: This mask is painted with Egyptian blue, the world’s oldest known synthetic pigment.

About 5,000 years ago, ancient Egyptians created a unique color now referred to as Egyptian blue. They used the pigment to decorate coffins, murals, and more. The synthetic, or human-made, compound was composed mostly of silicon (Si), copper (Cu), and calcium (Ca). But the method for creating the pigment had been lost to time . . . until now.

COURTESY OF MATT UNGER, CARNEGIE MUSEUM OF NATURAL HISTORY

BITS OF BLUE: A researcher takes a sample of blue pigment from an ancient Egyptian wooden falcon.

Chemists at Washington State University tested 12 recipes with different ratios of ingredients, baking them at 1,000°C (1,832°F) for up to 11 hours. They found that the most accurate Egyptian blue was produced by cooling the mixture slowly over time. “The fact that it is so challenging to reliably reproduce it speaks to the extreme talent of our ancestors in antiquity,” says John Stuart McCloy, who led the study.

WSU

TESTING RECIPES: Scientists tested different methods for re-creating Egyptian blue.

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