Bridgmanite: A New Name For the Earth’s Most Abundant Mineral

bridgmanite
Bridgmanite is the black material seen in a vein on the right side of this meteorite. Chi Ma / CalTech

You might expect that a substance that makes up more than a third of the Earth would, by now, have been well-studied and at the very least, named. But you’d be wrong.

In a study published this week in the journal Science, researchers finally came up with an official moniker for the mineral that makes up 38 percent of the Earth by volume: bridgmanite.

The reason this mineral is so difficult to study is because it is found deep underground in the Earth’s lower mantle, exposed to high temperatures and pressure, beyond the reach even of modern scientists. When it is removed from these conditions its unique crystal structure falls apart.

Strangely enough, researchers didn’t finally happen upon a sample of this substance from the Earth itself. Instead, they isolated it in a meteorite which they think was exposed to similar extreme heat and pressure conditions in outer space, before finally slamming into our planet.

The mineral was found in the Tenham meteorite, a specimen that crashed into the ground in Queensland, Australia, in 1879. But it was only recently discovered and found to contain bridgmanite, helping scientists better understand chemical process deep inside the Earth.

“The discovery concludes a half century of efforts to find, identify, and characterize a natural specimen of this important mineral,” wrote the researchers, from the University of Nevada-Las Vegas, CalTech and the University of Chicago, in the study.

It was previously known as “magnesium iron silicate in the perovskite structure,” or referred to as “silicate perovskite.” Not quite as catchy as bridgmanite. But minerals must be isolated from nature and carefully characterized before they can be officially named.

The substance is named after Percy Bridgman, the “father of high-pressure experiments,” who won the 1946 Nobel Prize in Physics.

In the study, the researchers used a device called a synchotron to send X-ray beams through the mineral and describe its crystal structure. The discovery will help better understand the physical processes at work in the Earth’s mantle, the layer between the crust and the core.