New Mineral Found Inside a Diamond That Formed 300km Underground

Every so often, mineralogy turns up something that sounds almost too specific to be real: a mineral that had only ever existed as a lab-made compound — including as an abrasive in toothpaste — discovered occurring naturally for the first time, sealed inside a diamond that crystallized over 300 kilometers below the Earth's surface.

That's exactly what happened with grahampearsonite (Ca₂P₂O₇, calcium pyrophosphate), found in a multi-phase inclusion inside a super-deep diamond from the Chapadão plateau in Brazil's Juina region. The International Mineralogical Association officially approved and named the mineral in 2026, honoring Dr. Graham Pearson of the University of Alberta for his decades of contributions to diamond research. Researchers believe grahampearsonite may be linked to the breakdown of another rare mineral, tuite, and could offer new insight into how phosphorus moves between Earth's crust and deep mantle — a process scientists still don't fully understand.

Diamonds that form this deep are exceptionally rare finds themselves, and the tiny mineral inclusions they carry up from the mantle are one of the only direct windows geologists have into conditions hundreds of kilometers underground. A new mineral species turning up in one is a genuinely significant event in the field.

It's a good reminder that the mineral world is still full of firsts — even in materials chemists thought they already understood.

Source: University of Alberta Folio, April 2026; American Mineralogist.