Primary source
Primary sources of mercury emissions can be natural or anthropogenic. Most natural mercury occurs as the mercury sulfide mineral, cinnabar, which is one of the only significant ores of mercury. Organic-rich sedimentary rocks can also contain elevated mercury. Weathering of minerals and geothermal activity release mercury to the environment. Active volcanoes are another significant primary source of natural mercury. Anthropogenic primary sources of mercury include gold mining, burning coal, and production of non-iron metals, such as copper or lead.