It weighs nearly a kilogram, and twinkles in various colours depending on which angle you glimpse.
The Fire of Australia was mined in 1946 in Coober Pedy, South Australia. It was found by Walter Bartram and stayed in the family until last week when the South Australian Museum announced the stunning opal was joining its permanent collection.
The uncut gem has been left in its original rough state except for two polished faces displaying the dazzling play of colour, mainly in red and yellow hues. It is thought to be the finest sample of its kind anywhere in the world, and the unique geology of South Australia contributed to its formation.
“When our state’s inland sea evaporated millions of years ago it provided a unique silica-rich environment for the creation of precious opal,” said the director of the museum Brian Oldman.
“It is these exceptional conditions that created the Fire of Australia.”
Precious opals take shape over millions of years as a solution of silica and water flows into voids and cracks between sedimentary rocks. The water then evaporates, leaving behind a minuscule layer of silica, and this process is repeated for many cycles.
It can take approximately five million years to get just one centimetre of opal sediment, and only some opals end up with the microscopic structure that turns them into glittery, colourful gemstones.
South Australia produces around 90% of the world’s precious opals, and Fire of Australia, which is bigger than a cricket ball, was discovered at Eight Mile, one of Australia’s richest opal fields.
In 1956 this field also yielded the largest and most valuable opal found to this day, the 3.45 kg Olympic Australis, valued at $2.5 million.
Fire of Australia has been a Bartram family heirloom since its discovery, although it has been on loan for many exhibitions around the world, including the South Australian Museum. It is valued at $900,000 and now has become part of the museum’s permanent collection thanks to a $455,000 grant from the Federal Government.
“After loaning the Fire of Australia to the South Australian Museum for its Opals exhibition, we made the decision to place this family heirloom in safe hands,” says Alan Bartram. The family decided to sell it to the museum for just $500,000 to ensure the gem would not be sold overseas and cut into smaller pieces.
If you want to catch sight of its unique sparkle in person, the precious opal will be on display in the foyer of the museum until 28 February this year.
All images courtesy South Australian Museum.