Sulfide Minerals

The sulfide minerals represent higher temperatures and a slightly deeper setting than the sulfate minerals, which reflect the oxygen-rich environment near the Earth's surface. Sulfides occur as primary accessory minerals in many different igneous rocks and in deep hydrothermal deposits that are closely related to igneous intrusions. Sulfides also occur in metamorphic rocks where sulfate minerals are broken down by heat and pressure, and in sedimentary rocks where they are formed by the action of sulfate-reducing bacteria. The sulfide mineral specimens you see in rock shops come from the deep levels of mines, and most display a metallic luster.