In 1951, an apple-sized meteorite was found just outside Wedderburn, Australia. For decades, scientists have been fascinated by the chunk of cosmic iron and nickel.

Now, researchers at Caltech identified a new type of mineral—never before seen occur naturally—in the meteorite, an indication that the rare meteorite came from the core of a planet that blew apart.

The Wedderburn meteorite is red and black and covered in scars from its long journey through space. Over the years, slices of the meteorite—originally about 7.8 ounces and held by Museums Victoria—have been sent out to researchers for analysis and now only about 2.5 ounces remain, reports Liam Mannix for Australian publication The Age.

Still, Chi Ma, a mineralogist at Caltech, and Alan E. Rubin, a cosmochemist at the University of California, Los Angeles, were able to get a piece of the meteorite to study last year. Looking at the rock closely, they were able to find tiny grains of a mineral called Fe5C2, which is a byproduct of iron smelting. By tradition, minerals aren’t named unless they are naturally occurring, so the team dubbed the substance edscottite in honor of pioneering cosmochemist Edward R. Scott who studies meteorites at the University of Hawaii at Manoa. Their description of the mineral appears in the journal American Mineralologist.

Stuart Mills, Museum Victoria's senior curator of geosciences, tells Mannix that the finding is very rare. “We have discovered 500,000 to 600,000 minerals in the lab, but fewer than 6,000 that nature’s done itself,” he says.

Exactly how the mineral formed is speculative. Geoffrey Bonning, a planetary scientist at the Australian National University not involved in the study, tells Mannix that it’s likely that the meteorite comes from the interior of a planet that formed in our early solar system. As dust and rock coalesced into a planet, the core heated up producing minerals like edscottite. At some point, that planet likely bashed into another planet, a moon or massive asteroid that smashed it to bits. Those chunks, including the rock that produced the Wedderburn Meteorite, then ended up in the asteroid belt between Jupiter and Mars where it circled for billions of years before another collision sent it toward Australia.

In the meantime, the museum is asking some of the laboratories around the world who received slices of the meteorite in decades past to return them to the museum so they will have enough material for planetary scientists to investigate.

This is not the only new natural mineral discovered recently. Last year, reports Hannah Osborne at Newsweek, researchers in Russia discovered a new mineral called uakitite in an iron meteorite that fell over the Uakit region of Siberia.

Caltech’s Ma found three new minerals in the Khatyrka meteorite in 2017 and has identified 19 new minerals in the Allende meteorite over the past decade. The minerals found in meteorites, are a lense into the early solar system. Of the 5,390 minerals discovered on Earth thus far, only about 65 are associated with meteorites, Ma told Franz Lidz at Smithsonian magazine earlier this year.

“The earliest minerals were formed by condensation from solar gases at high temperatures. These refractory minerals were the first solid materials in our solar system,” he says. “When you examine a meteorite down to micrometers and nanoscales, you can discover clues to what was happening when the rock was formed or when the sample was altered.”