Copper and boron, according to Wikipedia, will give green flame: https://en.wikipedia.org/wiki/Colored_fire https://en.wikipedia.org/wiki/Colored_fire But giv

Copper and boron, according to Wikipedia, will give green flame: https://en.wikipedia.org/wiki/Colored_fire https://en.wikipedia.org/wiki/Colored_fire But given the extreme conditions, a number of other factors could be at work.