Sound Waves Reveal Huge Cache of Diamonds

Study finds 1–2 percent of Earth’s oldest mantle rocks are made from diamond.

From MIT:

There may be more than a quadrillion tons of diamond hidden in the Earth’s interior, according to a new study from MIT and other universities. But the new results are unlikely to set off a diamond rush. The scientists estimate the precious minerals are buried more than 100 miles below the surface, far deeper than any drilling expedition has ever reached.

The ultradeep cache may be scattered within cratonic...