Unique 2000-year-old pearl found in WA

The price of a pearl is usually determined by its size, shape, colour and lustre, but archaeologists say a 2000-year-old near-round natural pearl uncovered in Western Australia is irreplaceable.

The historically significant Brremangurey rockshelter in the Kimberley's Admiralty Gulf was being excavated by a team from the University of Wollongong, University of New England and the Wunambal-Gaambera Aboriginal Corporation when the discovery was made.

Associate professor Kat Szabo said it was difficult to put a price tag on the pearl, which was found inside a shell midden, describing it as "irreplaceable".

"Pearls have not been recovered before from ancient sites in Australia," she said.

To avoid damaging the pearl, researchers developed non-destructive ways of examining it and established its age through radiocarbon analysis of surrounding shell midden material.

Micro-computed tomography - a form of micro CAT scan - was also used to ensure it was not a modern cultured pearl that had worked its way in.

The Brremangurey pearl and examples of Kimberley pearl shell valuables will be on display at the Lustre Exhibition at the WA Maritime Museum later this month.