• A fire rainbow is an extremely rare phenomenon that occurs only when the sun is high allowing its light to pass through high-altitude cirrus clouds with a high content of ice crystals. The misleading term “fire rainbow” is sometimes used to describe this phenomenon, although it is neither a rainbow, nor related in any way to fire. The term, apparently coined in 2006, may originate in the occasional appearance of the arc as “flames” in the sky, when it occurs in fragmentary cirrus clouds.
  • Diamond dust is a ground-level cloud composed of tiny ice crystals. This meteorological phenomenon is also referred to simply as ice crystals and is reported in the METAR code as IC. Diamond dust generally forms under otherwise clear or nearly clears skies, so it is sometimes referred to as clear-sky precipitation. Diamond dust is most commonly observed in Antarctica and the Arctic, but can occur anywhere with a temperature well below freezing. In the polar regions of Earth, diamond dust may persist for several days without interruption.Linked closely to haloes, diamond dust is a fog made of frozen droplets.It is a type of precipitation composed of slowly falling, very small, unbranched crystals of ice which often seem to float in the air; it may fall from a high cloud or from a cloudless sky, it usually occurs under frosty weather conditions (under very low air temperatures).

Images of Fire rainbow

    Image result for fire rainbow   Image result for fire rainbow

Images of diamond dust

Image result for diamond dust  Image result for diamond dust

(Images/videos taken from google/IE)