SA miners discover 'priceless' 65 million year old opalised pearls

Two miners have discovered the first known opalised pearls while sorting through a pile of dirt in South Australia.

The priceless four-millimetre scientific relics discovered in the Coober Pedy opal fields are the remnants of creatures dating back as far as 65 million years.

Miners Dale Price and Tanja Burks stumbled upon the discovery while sifting through a pile of soil, the ABC reports.

"The miners pick out anything that glows with ultraviolet light, because even a small chip of opal might be worth something if it's high quality with a high range of colours," Dr Ben Grguric from the SA Museum.

"It turns out these resembled pearls. A lot of the opal fossils, including bones and shells, were formed during the cretaceous period, which was an era earlier than 65 million years ago and the age of the dinosaurs."

Dr Grguric told the ABC pearls have been sent to the Australian Nuclear Science and Technology Organisation for further study.

The South Australian doctor said geological enthusiasts may encounter more opalised pearls in the future.