An incredibly rare Roman-era object—made from a substance that was once worth more than its weight in gold—has been discovered at an archaeological site in the United Kingdom. The item was ...

Archaeologists have made what is thought to be the first discovery of a prized purple pigment in Britain in a Roman bath-house near Hadrian’s Wall, revealing the importance of the building.

One reader wonders: Since purple dye was scarce, why didn’t people just combine blue and red? Illustration by Aurélia Fronty Q: I’ve heard that purple was called the royal color because ...