By Helen Briggs
Science reporter, BBC News
A reconstruction of the gold and turquoise beads as a necklace
A necklace found near Lake Titicaca in southern Peru is the oldest known gold object made in the Americas, archaeologists say.
Radiocarbon dating puts its origin at about 4,000 years ago, when hunter-gatherers occupied the area.
The researchers say it appears to have been fashioned from gold nuggets.
The discovery suggests that the use of gold jewellery to signify status began before the appearance of more complex societies in the Andes, they report.
Writing in the journal Proceedings of the National Academy of Science (PNAS), they say the artefact is the earliest worked gold found not only in the Andes, but the Americas as well.
Study leader Dr Mark Aldenderfer of the department of anthropology at the University of Arizona, Tucson, said it demonstrated an emerging social role for gold beyond simple decoration.
He told BBC News: "The gold reflects a universal tendency for human beings to strive for prestige and status.
"The gold reflects that process in people living in a simple society which is in the process of becoming more complex."
The necklace was found alongside the jawbone of an adult skull in a burial pit next to primitive pithouses at Jiskairumoko, a hamlet that was settled from 3,300 to 1,500 BC.
The researchers believe it had been worn by an adult, probably an elderly woman.
Marks on the necklace suggest that gold nuggets had been flattened with a stone hammer and then carefully bent or hammered around a hard cylindrical object to create a tubular shape.
The gold would have signalled the prestige of its wearer, "not at all different to today," said Dr Aldenderfer.
"This reflects a lot more than just a lovely object," he added. "This is a major piece of how people lived their lives and how they competed for status in the past."