Earliest Evidence of Indigo Processing Identified on Paleolithic Tools

Ca' Foscari University of Venice announced that when an international team of researchers first began to analyze 34,000-year-old stone tools found in the Dzudzuana Cave in the foothills of Georgia's Caucasus, they were just hoping to learn something about how they were used. However, as they peered closer, they uncovered incredible evidence of human behavior and complexity dating back tens of thousands of years. The pebble grinding tools contained traces of plant matter and indigotin, the deep blue compound also known as indigo. The results were stunning -- not only was this the first time that indigo has been found...