The blue color of lapis lazuli is due to a triatomic, radical anion of this element.
The blue color of lapis lazuli is due to a triatomic, radical anion of this element. Canyon Diablo troilite is used as the international reference standard for isotope ratios of this element. Sweetening gasoline involves oxidizing atoms of this element. Superheated water is pumped into the ground to extract this element in the Frasch process. This element is found with mercury in cinnabar and with lead in galena. Its most common allotrope is a crown-shaped ring containing eight atoms of it. It is found with iron in pyrite, or "fool's gold" and a very strong acid with this element at the center is made in the lead chamber process. For 10 points, name this nonmetal that forms yellow crystals. 
The blue color of lapis lazuli is due to a triatomic, radical anion of this element.
sulfur [accept S]