In the invisible architecture of clouds, a common mineral has long been doing extraordinary work — seeding ice at temperatures far warmer than physics alone would allow. Researchers at Bielefeld University and the University of Vienna have now explained, at the molecular level, why microcline — a potassium aluminum silicate found widely in atmospheric dust — nucleates ice so much more efficiently than its chemical siblings. The answer lies not in rare surface flaws, as scientists long assumed, but in the stable, ordinary face of the mineral itself, which carries an abundance of chemical anchor