Discoveries

September 26, 2023

Reasonably Precious

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Pink diamonds are renowned for their rarity and unique color, which is caused by their bent crystalline structure.

Around 90 percent of all these precious rocks are found in Australia’s Argyle Mine. Still, their origin has puzzled scientists for years, according to Live Science.

The mine and the diamonds are located at the edge of the continent and in a type of rock that is slightly different from the ones that usually bear diamonds.

Recently, new research showed that the formation of the rock and gemstones dates back to Earth’s ancient history – more than a billion years ago.

Previous studies in the 1980s estimated the age of the rocks in Argyle at about 1.2 billion years old, but there were doubts due to limitations in the technology used.

For this new study, researchers used a series of modern techniques, including laser ablation technology, to determine the diamonds’ age.

Their findings showed that the precious stones were formed around 1.3 billion years ago. This revised age coincides with the breakup of the supercontinent Nuna.

Some 1.8 billion years ago, two pieces of continental crust collided to create Nuna, and the area in which the Argyle mine now sits formed right at this collision point. It was also during this continental smash that the diamonds eventually got their appealing hue.

Nuna eventually broke up 500 million years later which brought these pink diamonds closer to the Earth’s surface.

While the Argyle mine was shut down in 2020, there’s a chance that similar pink diamond deposits exist elsewhere on Earth.

Even so, getting to them will be a challenge because they may be buried beneath layers of eroded rock and sediment.

This story originally appeared in the September 26, 2023 newsletter, Bricks and Blood.