Old Market House (Galena, Illinois) Old Market House (Galena, Illinois) The Old Market House, currently being operated as the Galena Welcome Center, is a brick building built in the Greek Revival style in 1845 in Galena, Illinois. It is owned and operated by the Illinois Historic Preservation Agency as an Illinois State Historic Site. The Old Market House was built by the city of Galena to serve as a city hall and enclosed public farmer's market. A rapid increase in population in the Galena area in the 1830s and 1840s, largely a result of the discovery of galena, a kind of lead ore found in
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