It'll be made of whatever gasses it's burning, which in their excited, combusting states are letting of heat and light of whatever colour they let off when burned. I'd say that's why different gasses burn in different colours.
@snottyotter started
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It'll be made of whatever gasses it's burning, which in their excited, combusting states are letting of heat and light of whatever colour they let off when burned. I'd say that's why different gasses burn in different colours.