text: Sulfur has four stable isotopes, with the following abundances: S (0.9502), S (0.0075), S (0.0421) and S (0.0002). These abundances are compared to those found in  Cañon Diablo troilite. Variations in sulfur isotope ratios are used to study the origin of sulfur in an orebody and the temperature of formation of sulfur&ndash;bearing minerals as well as a biosignature that can reveal presence of sulfate reducing microbes.