Highest occurrence of diamond dust

"Diamond dust" is a ground-level cloud composed of ice crystals that form in the presence of a temperature inversion. Plateau Station, a now-disused US research station on the central Antarctic Plateau, can experience on average 316 days each year on which diamond dust clouds form.

Diamond dust is much thinner than fog and can have zero effect on visibility. It is also known a clear-sky precipitation as it can form without any overhead cloud. It can be seen as flashes of light as sunlight is reflected and refracted from the individual ice crystals, which are usually hexagonal or columnar in shape. It is most common in the polar regions.