like honey pink diamonds They are some of the most precious and valuable minerals in modern society due to their extreme rarity at the surface. However, there is one impressive detail. It is estimated that most of them – more than 90% according to experts and various studies – were extracted from one place. It is mine Argylewhich is located in the northwest of Australia, very close to the coast of the continent.
For nearly four decades, until its closure in November 2020, Argyle was the largest producer of colored diamonds on the planet and virtually the only deposit that, for some strange reason, provided the Earth’s crust with pink minerals.
However, after many years of mystery, a team of scientists led by an Australian geophysicist Hugo OlierrockIt seems they finally found out why the Argyle mine was so different from the others. Their findings, which have to do with the breakup of an ancient supercontinent, were published in an article in the journal Nature in September of this year.
The closed Argyle mine is located in the Kimberley region of northern Western Australia, almost on the edge of the continent. Photo: David Gardiner/Flickr
Origin of Argyle diamonds
When geologists analyzed the pink Argyle crystals and measured the age of their elements, they found that they formed about 1.8 billion years ago, when a fragment of what is now Western Australia’s tectonic plate collided with that of northern Australia. After this event, the minerals remained in the depths of the Earth.
Olierrok, a researcher at Curtin University, explains that diamonds take on a certain color when their crystalline structure is subjected to different pressures. In this sense, light pressure will cause the clear glass to turn pink and with more pressure it will turn brown.
Diamonds get their pink color from the extreme pressure they experience deep in the mantle. Photo: Rio Tinto
Argylian minerals have been trapped in the Earth’s mantle (a 2,900 km thick layer that begins 33 km deep below the continental surface) for several million years. However, everything changed when they were violently thrown to the surface by a violent movement in plate tectonics. 1.3 billion years.
According to Olierrok and his colleagues, the date of this event roughly coincides with the fragmentation process Colombiathe first supercontinent in recorded history.
Fragmentation of Colombia
Several studies have found a relationship between the occurrence of diamonds on the surface and the separation of continents. For that reason, it is not surprising that the Argyle Pink Gems appeared after the breakup of the supercontinent Columbia, also known as Show.
According to the research, the pink diamonds would originate from the thinnest layers of the crust, which in this case corresponded to the continental margin. This would also be the reason why the Argyle mine, unlike other mineral deposits, is located near the coast and not in the central part of the continent.
The appearance and relocation of the Argyle mine (star symbol) in Australia after the collapse of Columbia. Photo: Olierook et. k. (2023) / Nature
“Argyle lies where the Kimberley region and the rest of northern Australia collapsed many years earlier, and this type of collision creates a damaged area or ‘scar’ on Earth that will never fully heal,” Olierook said in an interview.
“While the continent that would become Australia did not break apart, the area where Argyle is located stretched, including the scar, creating gaps in the Earth’s crust through which magma shot to the surface, bringing the pink diamonds with it,” he explained.
More information on the topic:
How many diamonds did the Argyle mine produce?
While the Argyle mine was in operation, it produced more than 865 million carats of rough diamonds, according to Río Tinto, the multinational mining group that was in charge of mining the deposit.
The vast majority of diamonds were white, brown, champagne, blue and purple. Meanwhile, very few of them were pink.
How much are pink diamonds worth?
According to the Australian Pink Diamond Exchange, the price per carat of pink diamonds varies depending on their color intensity.
These pink gems, which are clear or light, sell for between $3,000 and $8,000; those with medium intensity, between $10,000 and $30,000, and those with more intense pink, between $30,000 and $100,000.
The most expensive pink diamond ever sold was a diamond Eternal pinkwhich was found in a mine in Botswana in 2019. It sold at auction for more than $35 million.
The Eternal Pink was auctioned for over $35 million. Photo: South China Morning Post
