Shortly after its close in the 1960s, a mine in Tennyson, Wis., flooded with groundwater. Recently, scuba divers exploring the mine’s spooky depths spotted unusual, spongy red masses. The red slime, it turns out, contains the first evidence of a type of crystal formation seen previously only in laboratories.
Generally, crystals form when atoms or molecules in a solution slowly stack together. Over the past decade, however, researchers including Jillian F. Banfield at the University of Wisconsin–Madison have grown crystals from larger starting particles called nanocrystals, each with hundreds or thousands of atoms or molecules.