Most diamonds form at depths exceeding 150 kilometers in the Earth’s mantle, but they only reach the surface through special volcanic eruptions—and researchers have now discovered the forces behind this process.
Scientists have determined that water and carbon dioxide play the key role in the ascent of diamonds. They make the magma lighter than the surrounding rock, allowing it to rise rapidly to the surface at speeds up to 130 km/h (80 mph).
According to the U.S. Geological Survey, over 70% of the world’s diamonds are extracted from kimberlite pipes—distinct channels in the Earth’s crust through which the precious crystals and rocks break out.
Computer modeling showed that for a kimberlite eruption to occur, the CO2 content in the magma must be at least 8.2%. Water makes the molten rock more fluid, while carbon dioxide maintains its structure at depth. As it nears the surface, the gas bursts out, creating an “explosive effect” that carries the diamonds to the light.
This discovery has brought science closer to solving one of the most important geological processes that allows humanity access to the rarest and most valuable minerals.
