In the quest to understand cloud formation, one mineral has been a central point of curiosity. Microcline is a potassium-rich type of feldspar, a class of minerals that accounts for 60% of Earth’s crust. More importantly for clouds, ice nucleation occurs unusually easily around microcline—and atmospheric scientists don’t know why.
Ice nucleation doesn’t necessarily happen at the mineral’s surface, but to solve the mystery, researchers still needed to see what the atomic structure looked like at the surface. Researchers led by Ulrike Diebold of the Technical University of Vienna used a new technique to prepare their sample for microscopy.1 They found a honeycomb pattern of aluminum and silicon surrounding potassium ions that aligned with expectations of the field. Angelika Kühnle of Bielefeld University in Germany and colleagues found similar results using a different preparation technique.2 The two groups’ findings are an important stepping stone in understanding the complexities...
