DnD headcanon: Fire Genasi - the kind heavily touched by Inferno, who have hair made of heat and flickering light - use metal salts to dye their hair. Chlorides of sodium, barium, and calcium give a conventional golden or blonde look, but rowdy teen planetouched dye their hair magenta with lithium, or chartreuse with boric acid. On formal occasions - weddings, religious ceremonies, state galas - they limn their hairlines with finely ground magnesium, to place sun-bright sparkles in their hair.
Specific details of colours here: https://en.wikipedia.org/wiki/Flame_test












