Geoscientists have for the first time revealed the magma plumbing beneath Mount St. Helens, the most active volcano in the Pacific Northwest. The emerging picture includes a giant magma chamber, between 5 and 12 kilometers below the surface, and a second, even larger one, between 12 and 40 kilometers below the surface. The two chambers appear to be connected in a way that could help explain the sequence of events in the 1980 eruption that blew the lid off Mount St. Helens.

There’s diamond under them thar plants. A geologist has discovered a thorny, palmlike plant in Liberia that seems to grow only on top of kimberlite pipes—columns of volcanic rock hundreds of meters across that extend deep into Earth, left by ancient eruptions that exhumed diamonds from the mantle. If the plant is as choosy as it seems to be, diamond hunters in West Africa will have a simple, powerful way of finding diamond-rich deposits. Prospectors are going to “jump on it like crazy,” says Steven Shirey, a geologist specializing in diamond research at the Carnegie Institution for Science in Washington, D.C.