The diamond originally came from the transition zone of the Earth’s mantle. The transition zone is located several hundred kilometres below the surface. That’s where high temperatures and pressures create ringwoodite out of olivine, another mineral.

Gros Morne National Park

The transition zone is part of the Earth’s mantle, and is located between the lower mantle and the upper mantle, between a depth of 410 and 660 km (250 to 400 mi). The Earth’s mantle, including the transition zone, consists primarily of peridotite, an ultramafic igneous rock.

The finding, published in Science, suggests that a reservoir of water is hidden in the Earth’s mantle, more than 400 miles below the surface. It extends deep into the Earth’s interior as the oceanic crust subducts, or slides, under adjoining plates of crust and sinks into the mantle, carrying water with it. “

Only two gemstones form in the Earth’s mantle. Most gemstones form in the Earth’s crust. Only two gemstones form in the Earth’s mantle – the diamond and the peridot. These are gems that crystallise at extremely high temperatures.

1) Diamond Formation in Earth’s Mantle. Geologists believe that the diamonds in all of Earth’s commercial diamond deposits were formed in the mantle and delivered to the surface by deep-source volcanic eruptions. These eruptions produce the kimberlite and lamproite pipes that are sought after by diamond prospectors.

Much of the planet’s mantle consists of magma. This magma can push through holes or cracks in the crust, causing a volcanic eruption. When magma flows or erupts onto Earth’s surface, it is called lava. Like solid rock, magma is a mixture of minerals.

The core is made of two layers: the outer core, which borders the mantle, and the inner core. The boundary separating these regions is called the Bullen discontinuity.