A museum in outback Queensland, Australia, has revealed a fossil pearl dating back 100 million years, a discovery described by scientists as one of the rarest of its kind.

The marble-sized sphere, about two centimeters across, went on display at the Kronosaurus Korner Museum in Richmond. The pearl was first unearthed in 2019 during a public dig, when a visiting tourist lifted a fragment of an Inoceramus shell from the museum’s excavation site.