Galena in the eye cosmetic kohl. In Ancient Egypt, this was applied around the eyes to reduce the glare of the desert sun and to repel flies, which were a potential source of disease. galena is the primary ore of lead, which is mainly used in making lead–acid batteries; however, significant amounts are also used to make lead sheeting and lead shot. Galena is often mined for its silver content, such as at the Galena Mine in northern Idaho. It is also used in pencils in the older times. Also known as "potter's ore", galena is used in a green glaze
Mineral hydration Mineral hydration Mineral hydration is an inorganic chemical reaction where water is added to the crystal structure of a mineral, usually creating a new mineral, usually called a "hydrate". In geological terms, the process of mineral hydration is known as "retrograde alteration" and is a process occurring in retrograde metamorphism. It commonly accompanies metasomatism and is often a feature of wall rock alteration around ore bodies. Hydration of minerals occurs generally in concert with hydrothermal circulation which may be driven by tectonic or igneous activity. There are two main ways in which minerals hydrate. One is conversion of an oxide