The mercury available on the world market is supplied from a number of different sources, including (not listed in order of importance):
Mine production of white mercury mining process (meaning extracted from ores within the earth’s crust):
either as the main product of the mining activity, or as by-product of mining or refining of other metals (such as zinc, gold, silver) or minerals;
Recovered primary mercury from refining of natural gas (actually a by-product, when marketed, however, is not marketed in all countries);
Reprocessing or secondary mining of historic mine tailings containing mercury;
Recycled mercury recovered from spent products and waste from industrial production processes. Large amounts (“reservoirs”) of mercury are “stored” in society within products still in use and “on the users’ shelves”;
Mercury is a natural component of the earth, with an average abundance of approximately 0.05 mg/kg in the earth’s crust, with significant local variations. Mercury ores that are mined generally contain about one percent mercury, although the strata mined in Spain typically contain up to 12-14 percent mercury. While about 25 principal mercury minerals are known, virtually the only deposits that have been harvested for the extraction of mercury are cinnabar. Mercury is also present at very low levels throughout the biosphere. Its absorption by plants may account for the presence of mercury within fossil fuels like coal, oil, and gas, since these fuels are conventionally thought to be formed from geologic transformation of organic residues.