Diamonds have been created at room temperature in a lab

Natural diamonds are usually formed over billions of years, about 150 km deep in the Earth where there are high pressures and above 1000°C.

Researchers created diamonds from bits of carbon in a lab at room temperature by applying an extraordinary amount of slightly off-axis pressure.

The scientists were able to make two types of diamonds: the usual kind you'd find in an engagement ring, and Lonsdaleite diamonds. Lonsdaleite diamonds are naturally produced at meteorite impact sites. They're about 58% harder than other diamonds, and have a different crystalline structure.

While diamonds form normally as a result of extreme pressure and heat, it turns out that pressure alone can do it if it's applied in the right way, even at room temperature.

The pressure they exerted was considerable—the equivalent of the weight of about 640 African elephants concentrated on a very small area.

The team used cutting-edge advanced electron microscopy to image slices of experimental diamond samples that provided a peak into their formation.

One revelation was the relationship between the two diamond types. The regular diamonds only form in the middle of these Lonsdaleite veins. Seeing these little rivers of Lonsdaleite and regular diamond for the first time was just amazing and really helps understand how they might form.

The twist in the story, is how they apply the pressure. As well as very high pressures, we allow the carbon to also experience something called 'shear' — which is like a twisting or sliding force. They think this allows the carbon atoms to move into place and form Lonsdaleite and regular diamonds.

While many may think of diamonds only for their ornamental value, their hardness makes them excellent for cutting through most anything, and they're used in some of the world's most advanced precision cutting systems.

Lonsdaleite [in particular] has the potential to be used for cutting through ultra-solid materials on mining sites.