Most people understand that the crust – the layer all living things on Earth occupy – is relatively thin. Instead, most of Earth’s volume is made up by the mantle, a thick, rocky layer beneath the surface. Though scientists have long known that the lower part of the mantle is mostly made of a silicate mineral with a perovskite structure, a lack of surface samples made it difficult to prove. Thanks to one meteorite, scientists from UNLV and Caltech have finally found their sample.

They’ve named the new mineral bridgmanite, in honor of Percy Bridgman, a physicist who won the 1946 Nobel Prize in Physics for his fundamental contributions to high-pressure physics.

“This finding fills a vexing gap in the taxonomy of minerals,” says Oliver Tschauner, an associate research professor at the University of Nevada-Las Vegas who identified the mineral along with Ching Ma, a mineralogist and director of the Geological and Planetary Sciences division’s Analytical Facility at Caltech.

Previous estimates of the lower mantles makeup came from chemical experiments and seismic data. However, since it lies some 400 miles below the Earth’s surface, samples don’t often find their way to the top, and researchers certainly can’t make their way down.

The Tenham meteorite, where the sample was located, is actually not new – it was found in Australia in 1878. Since it must have survived high-impact collisions in order to become a meteorite, Tschauner and Ma figured it might have experienced the high-pressure conditions that lead to bridgmanite in Earth’s mantle. As it turns out, they were right.

The mineral and the mineral name were approved on June 2 by the International Mineralogical Association’s Commission on New Minerals, Nomenclature and Classification.

“It is a really cool discovery,” says Ma. “Our finding of natural bridgmanite not only provides new information on shock conditions and impact processes on small bodies in the solar system, but the tiny bridgmanite found in a meteorite could also help investigations of phase transformation mechanisms in the deep Earth.”