frost

Ice crystals formed by the direct deposition of water vapor onto surfaces cooled below freezing — a process that skips the liquid phase entirely, vapor becoming solid on contact. Frost is not frozen dew; it is built molecule by molecule from the air itself. The patterns it creates on glass — fernlike, feathered, fractal — are among the most intricate structures produced by any natural process. A hard frost kills the growing season. A light frost merely announces the change.