Mercury sulphide, more commonly known as Cinnabar, has been our primary source for elemental mercury since the earliest days of human civilization. Mercury has traditionally been used as a pigment for ceramics and tattoos, though in the modern age, it’s been employed in a wide variety of scientific equipment like thermometers and barometers, as well as a number of heavy industrial applications like precious metal reclamation and chlorine production, not to mention the mercury switches that help modern electronics work. However, when oxidized, this element will produce methyl mercury and dimethyl mercury, two toxic compounds that cause irreparable harm to the nervous systems of children. It is deadly in small concentrations and can be absorbed through the respiratory tract, intestines, or skin.
Both sulphur and sulphuric acid are both used extensively throughout industry. Sulphur can be found in everything from matches and tires to fungicides and fumigants while sulphuric acid is a vital component of many industrial processes from pigments to explosives. And at one time, Pyrite, a compound mineral formed from iron and sulphur, was the only place to get them.
This lead to extensive pyrite mining efforts, which in turn lead to devastating environmental damage as the sulphide mine tailings acidified groundwater and nearby streams. Plus, pyrite has a nasty habit of spontaneously combusting when it’s mixed into coal seams and exposed to air, releasing highly toxic metals like Arsenic into the atmosphere as it oxidizes. This is why many coal mines will spray limestone powder onto newly excavated coal seams—it slows the ore’s exothermic oxidation reaction enough to prevent it from exploding.
This gorgeous green gemstone is called Fluorite. Composed of calcium fluoride, it’s commonly found in veins of other ores like iron, coal, and copper. The stone can be used as a smelting flux, though it’s more often seen in jewelry and the lenses of telescopes. And when mixed with sulphuric acid, fluorite produces hydrogen fluoride, an important industrial chemical precursor.
However, fluorite can be quite dangerous to both those who handle it regularly and those who simply happen to live near a flourite mine. Fluorite contains fluorine, a soluble mineral that readily leaches into groundwater supplies and can be absorbed by the lungs if ground into dust or burned in a coal-fired stove.
Once fluorine is in the body, it causes skeletal fluorosis—a painful disease that weakens bones and damages joints. Many rural communities throughout India, China and the rest of Southeast Asia have been beset by outbreaks of the disease due to people drinking contaminated water, as is the case in India, or inhaling the mineral as a fine particulate, as is the case in China. An estimated 10 million people are thought to be afflicted by it in China’s Guizhou province alone.
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