I can be found near gentle green hills and stony mountains,
Alongside the gas in the clouds and the iron of the earth,
At times I can be white and frosty, red and fiery, or blue and stormy,
What am I?
I seem to have made this riddle too broad, so these hints should help someone solve it:
1) I've mixed my metaphors everywhere, so "white and frosty" refer to two different things.
2) Four of the clues are related by the same field of science.
3) Knowledge tag: There are several clues that I disguised by making the words plural or ending in 'y'. They are all related to each other in some way, but it requires some specific knowledge.