4,990-carat 'Fire Of Australia' Opal Valued At $686,000 Illuminates South Australian Museum's Front Foyer

The Fire of Australia, known as the world’s most valuable piece of rough opal, has taken up permanent residence in the South Australian Museum’s Opal Collection. Valued at $686,000 (AU$900,000), the opal was purchased for AU$500,000 through the generosity of a private donor and AU$455,000 in funding from the Australian government’s National Cultural Heritage Account. The uncut, 4,990-carat opal is now on public display in the front foyer of the Adelaide-based museum.

Nicknamed “The Monster," the unique gem comes with an equally unique history. In 1946, prospector Walter Bartram was working his dusty terrain at the prolific Eight Mile field in Coober Pedy, South Australia, about 466 miles north of Adelaide, when he staked a claim to what became known as the Fire of Australia.

"At the end of the war all of the sons and siblings and greater families were all invited to come and join in this prolific field, which was absolutely exceptional and not very deep so they could do it with hand mining," said Alan Bartram, Walter’s son. "Everybody that was there was successful, some to a huge extent."

The brilliant, 998-gram (2.2 pound) opal has been in Bertram’s family for more than 60 years. According to the BBC, the opal has mostly been kept in a safe deposit box since being unearthed with a pick and shovel more than 70 years ago.

“After loaning the Fire of Australia to the Museum for its Opals exhibition, we made the decision to place this family heirloom in its safe hands,” said Bartram. "It seems fitting that it should be passed onto the people of South Australia to enjoy.”

Though still in its rough condition, two faces of the Fire of Australia have been polished, revealing the rare gem’s exceptional quality. Its kaleidoscope of colors transition from deep green to bright yellow to dark red, depending on the viewing angle.

“The Fire of Australia is the largest piece of high-quality light opal rough in existence,” Collection Manager Ben McHenry McHenry said. “Ordinarily, it would have been cut up for the jewelry trade. Keeping it in its current form gives the museum the opportunity to display to its visitors just how magnificent opal in the rough can be.”

Museum Director Brian Oldman also praised the rare and unique quality of the stone.

“Opal of this quality can only be created under certain climate conditions,” Oldman told ABC. "When our state's inland sea evaporated millions of years ago, it provided a unique silica-rich environment for the creation of precious opal. It is these exceptional conditions that created the Fire of Australia.” The opal's rarity should not be underestimated, he noted.

According to the South Australian Museum, opals are the most visited exhibition in the Museum’s history, resulting in donations of $3 million+ in precious opals, including the Fire of Australia.

Bartram remarked to ABC News that while he could have raised a much higher price for the Fire of Australia at international auction, it was important to him that it remained in South Australia. "It is such a piece, so outstanding that it would have been a sheer misery to see it go to another destination and be cut up for watch faces or something like that," he said.

The mining town of Coober Pedy still draws crowds enticed by the fantasy of striking it rich.

“South Australia supplies about 90% of the world's quality opals, so there may be more major finds," Bartram said.

The Museum will proudly display the Fire of Australia opal in its front foyer until February 28, 2017.