Natural History (Pliny) developed for counterfeit coins and proved very popular with the victims, mostly ordinary people. He deals with the liquid metal mercury, also found in silver mines. He records that it is toxic, and amalgamates with gold, so is used for refining and extracting that metal. He says mercury is used for gilding copper, while antimony is found in silver mines and is used as an eyebrow cosmetic. The main ore of mercury is cinnabar, long used as a pigment by painters. He says that the colour is similar to "scolecium", probably the kermes insect. The dust is very toxic, so
Iron ore over a slurry containing magnetite or other agent such as ferrosilicon which increases its density. When the density of the slurry is properly calibrated, the hematite will sink and the silicate mineral fragments will float and can be removed. Iron is the world's most commonly used metal - steel, of which iron ore is the key ingredient, representing almost 95% of all metal used per year. It is used primarily in structural engineering applications and in maritime purposes, automobiles, and general industrial applications (machinery). Iron-rich rocks are common worldwide, but ore-grade commercial mining operations are dominated by the countries listed