Scientists have found hidden cracks and centuries of decay that help tell the story of a dinner plate that serves as Australia's oldest record of early European explorers.
The priceless 315-year-old plate was flown to Melbourne in a reinforced case and a padded crate for testing at the Australian Synchrotron - a football field-sized facility that accelerates electrons to near the speed of light - for the first time last week.
After 121 years of being battered by the elements on Dirk Hartog Island since it was put there by Dutchman Willem de Vlamingh in 1697, the plate is damaged, corroded and in need of constant protection.
It has rarely travelled from its display case at the WA Museum's Shipwreck Galleries in Fremantle because of its fragility.
Previous studies of the plate have been limited to what historians could see scratched on its surface.
But the museum wanted to find out the plate's composition and analyse its decay patterns in the hope it could travel overseas for the 400th anniversary of the first European contact with Australia in 2016.
WA Museum executive director Ian MacLeod, who is an expert in metals corrosion and conservation and flew to Melbourne with the de Vlamingh plate, said intensive testing had found hidden scratch marks from knives, confirming it had been used as a plate.
Dr MacLeod said the corrosion patterns revealed it had been nailed to a post at Cape Inscription, facing the ocean. It later fell from the post, facedown, which for many years preserved its inscription.
He said the plate was about 85 per cent tin and pewter, which was typical of the period, but also had a halo of copper, zinc and arsenic around the nail holes.
It had also been confirmed the plate had been stamped, not engraved.
"It is telling a much richer story," Dr MacLeod said."The level of detail we've collected from the synchrotron scans has provided us with a roadmap to decay, if you like, which will enable us to conserve this very important part of Australia's early history for future generations."