When the earth experiences fiery volcanic eruptions, diamonds are blasted into the sky and fall to the ground. This phenomenon has baffled scientists, but researchers recently made a discovery that shed light on the geological bling and where it may likely be found. 


An international team of scientists observed that over the past billion years, most of these outbursts took place 25 million years after continental plates (a.k.a. the incrementally moving slabs of Earth’s crust) tore apart. The researchers collected historical data describing the plates’ movements and studied kimberlites, the rocks tossed into the air that hold the gems, to learn more about the spectacle, The Guardian reported.


With help from computer models, scientists put together the sequence of events that led to these diamond-rich eruptions. When the continental plates get stretched, they begin to sever. This tearing makes rock thinner and changes the flow of material within the earth’s mantle. This disturbance is powerful enough to cause chunks of rocks to break away from the plate, and those pieces experience enough pressure that carbon deposits located there can make a diamond over the course of hundreds of millions of years. 

“We know where, when, and why kimberlites are forming and that’s really useful for exploration,” Professor Tom Gernon, a geologist at the University of Southampton and the leader of the study, told The Guardian. “We know the events needed to trigger this domino effect, and by joining the dots, we can target those areas that hold the most promise for diamonds to be there in the first place.”

When heaps of rock sink into the mantle, there’s even more disruption to the flow, causing it to spread outwards. Additionally, layers of rock on the bottom of the plate get displaced. The confluence of these factors create diamond-bearing kimberlite magma. When enough has formed, the molten rock erupts, shooting through the Earth’s crust. 

“These eruptions are quite rare in Earth’s history because they require this perfect storm of conditions and events to generate them,” Gernon said. “The dinosaurs would have been walking around in some of these areas, watching these events, and they would have been quite perplexed. They are extremely rapid events and they probably wouldn’t be expecting them.”