Early pre-Hispanic use of indigo blue in Peru

Archaeological research has identified the use of cultivated cotton ( Gossypium barbadense ) in the ancient Andes dating back to at least 7800 years ago.

Because of unusual circumstances of preservation, 6000-year-old cotton fabrics from the Preceramic site of Huaca Prieta on the north coast of Peru retained traces of a blue pigment that was analyzed and positively identified as an…

Source: Early pre-Hispanic use of indigo blue in Peru | Science Advances