An Australian museum said on Monday it will exhibit what it believes is the best opal stone ever found - a 6-cm multi-colored gem found in the Outback named the Virgin Rainbow.

The South Australian Museum said the stone, valued at more than US$730,000, will go on public display for the first time in September to mark the centenary of opal mining in the country. "It's of unequaled quality," said museum director Brian Oldman.

"It's almost as if there's a fire in there - you see all different colors. As the light changes, the opal itself changes. It's quite an amazing trick of nature."

Dug up in the South Australia desert town of Coober Pedy in 2003 by local miners, the Virgin Rainbow came into the museum's possession about 18 months ago and will be part of an exhibition opening in Adelaide next month.

About 90 percent of the world's opals come from South Australia, which was once covered by an inland sea that over millions of years provided an ideal environment for the formation of the stones.

"I think this exhibition will feature the finest collection of precious opals that we believe have been brought to one place in the world," Oldman said.

Opals were first discovered at Coober Pedy - widely-known as the opal capital of the world - in 1914 by a boy named Willie Hutchison who was on a gold mining expedition with his father.

"The story goes that Willie set out in search of water one day, rather than staying at camp as he'd been instructed to do by his father," Oldman said.

(China Daily 08/04/2015 page10)