On 
a far-off planet known as OGLE-TR-56b (a "hot Jupiter" which orbits its star in about the length of a terrestrial day), a hellish weather phenomenon may occur: 
Intriguingly, the temperature of OGLE-TR-56b's upper atmosphere is  theoretically just right to form clouds, not of water vapor, but of iron  atoms. Earlier this year, astronomers reported evidence for iron rain  on brown dwarfs. However, such storms only occur over a short portion of  a brown dwarf's lifetime, while the newly discovered 4 billion year-old  OGLE-TR-56b should still be experiencing this exotic weather, thanks to  strong heating from the nearby star.
Elsewhere in the cosmos, 
in the nebula surrounding a newly-forming star, it rains crystals of a green mineral called olivine:
"We propose that the crystals were cooked up near the surface of the  forming star, then carried up into the surrounding cloud where  temperatures are much colder, and ultimately fell down again like  glitter." ...
"If you could somehow transport yourself inside this protostar's  collapsing gas cloud, it would be very dark," said Charles Poteet, lead  author of the new study, also from the University of Toledo. "But the  tiny crystals might catch whatever light is present, resulting in a  green sparkle against a black, dusty backdrop."
Illustration of the crystal rain from 
NASA