Sulfur

Sulfur is a bright yellow, solid nonmetal that conducts electricity poorly. Pure sulfur is odorless: the familiar rotten-egg smell comes from its compound hydrogen sulfide. Sulfur occurs naturally around volcanoes and hot springs, and in minerals such as pyrite, a sulfide, and gypsum, a sulfate. Today, most commercial sulfur is recovered as a by-product of cleaning natural gas and refining petroleum. Sulfur-containing impurities are removed and converted into elemental sulfur. Its main use is making sulfuric acid, which is important in fertilizer production. Sulfur also helps strengthen rubber through vulcanization, a process that creates links between rubber's long molecules.