Bismuth is somewhat similar to antimony. Bismuth makes a thin coating of bismuth(III) oxide when it is in air. This makes the colors on the crystals. It does not oxidize any more than the oxide layer. It burns when powdered with a bright blue flame, making yellow bismuth(III) oxide fumes. Bismuth reacts with sulfur when molten as well. Bismuth reacts with nitric acid to make bismuth(III) nitrate and concentrated sulfuric acid to make bismuth(III) sulfate and sulfur dioxide. It reacts with the halogens to make bismuth(III) halides. With fluorine it makes bismuth(V) fluoride unless the fluorine is diluted, though.