Green fire is one of the most vibrant forms of colored flames. It’s also one of the easiest to produce with common materials!
Borax or Boric Acid Green Fire
Borax and boric acid are two boron salts. Find borax in the store as a laundry detergent booster or household cleaner. Stores sell boric acid as a roach killer or as a disinfectant. Adding either chemical to a fire yields a vivid green flame.
For best results, mix either borax or boric acid with methanol, a type of alcohol, and ignite the solution. The alcohol burns off, leaving behind a white residue from the boron compound. Add more alcohol when you want more colored fire. But, always make certain the flame is completely extinguished before adding additional liquid fuel. The boron compound is not consumed, so it can be re-used.
Copper Sulfate Green Fire
Copper sulfate is an algicide and root killing agent. If you have copper sulfate solution, soak logs or pinecones in the liquid and let them dry before igniting them. Sprinkle solid copper sulfate onto a fire to impart a green flame.
Copper sulfate dissolves in rubbing alcohol and produces pure green fire. The copper compound is not consumed by the fire, so adding more fuel maintains the color. This compound also works on a wood or charcoal fire, although expect a rainbow of colors from the interaction with other chemicals in the fuel.