It's well-documented that copper sulfate can be introduced to certain fuels to burn green. If one was to scale up the fireworks, so to speak, then I'm not so sure how to explain the mechanics of it all.

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While copper sulfate was the inspiration for this question, I'm by no means limiting answers to using it. Just aiming to explain green volcanic eruptions / lava by any scientific means necessary.


Specifically, if a world is to have green-colored volcanic eruptions, then, geologically-speaking what kind of composition in the crust / mantle / atmosphere would be needed? Essentially, anything that is scientifically plausible is fair game.

Bonus points: Would be nice to still have a habitable world for humans. Not strictly necessary however.

  • $\begingroup$ Required reading about how hot things glow: black body, black body radiation. The second table even has a nice infographic with the possible colors. $\endgroup$
    – AlexP
    Commented Mar 7, 2022 at 10:16

1 Answer 1


Although many volcanic rocks actually turn greenish when cooled (such as olivine) they aren't going to look that way when molten. Anything hot enough to melt rock is going to emit light mainly in the red part of the spectrum until it is hot enough to turn white.

But lava isn't the only stuff that can spew out of holes in the ground. Regular geysers erupt with water periodically, and this water can have stuff dissolved in it that might give it a green hue, such as the aforementioned olivine. It probably won't be nearly as vibrant as in your picture, but it should suffice for a "green gusher".

  • $\begingroup$ Interesting. Perhaps there could be some hypothetical mantle composition that has a (lower?) melting point? Or whatever is required for the volcano to emit light in the green part of the spectrum. $\endgroup$ Commented Mar 7, 2022 at 9:18
  • $\begingroup$ @ArashHowaida I was going to suggest cryovolcanoes, actually - basically volcanos on very cold planets, where the "rock" is ice and the "subterranean molten rock" are substances that would be liquid on Earth, but are only liquid underground on an ice planet. But those planets are generally not human-habitable, and you get the same effect from a geyser anyway, so that seemed to be a better answer. $\endgroup$ Commented Mar 7, 2022 at 10:03

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