Do you know the diamond on your finger is most likely made recycled minerals by Earth below the ocean floor?
Diamonds are crystals of carbon formed beneath the Earth's crust. They are brought to the surface in volcanic eruptions of a special kind of magma called kimberlite.
A new study by geoscientists at Macquarie University, Sydney, found out that traces of salt trapped in many stones show that they were formed from ancient sea beds, buried under the crust for millions of years.
Researchers recreated extreme pressures and temperatures found 200 kilometres below ground to achieve the results. And from these studies they found, seawater in sediment from the bottom of the ocean reacts to produce the same composition of salts found in diamonds. Most diamonds found at the Earth's surface formed in this way according to the researchers.
Diamonds that are carved into gemstones are mostly pure-carbon in their composition. But there is another kind — 'fibrous' diamonds. They are cloudy, less appealing and not used in jewellery. Instead, they are used for industrial purposes, eg drill bits.
Fibrous diamonds come with traces of sodium, potassium or other minerals that reveal information about the environment where they formed. This salty fluid found in these diamonds provided the base of study for researchers.
The study, published in Science Advances puts an end to an age-old question about the formation of diamonds.
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