Metamorphic reaction

Image:Metamorphic reaction EN.svg; chl = chlorite; ep = epidote; gt = garnet; hbl = hornblende; plag = plagioclase. Two minerals represented in the figure do not participate in the reaction, they can be quartz and K-feldspar. This reaction takes place in nature when a mafic rock goes from amphibolite facies to greenschist facies.]]

A metamorphic reaction is a chemical reaction that takes place during the geological process of metamorphism wherein one assemblage of minerals is transformed into a second assemblage which is stable under the new temperature/pressure conditions resulting in the final stable state of the observed metamorphic rock.{{cite web

|url=http://www.tulane.edu/~sanelson/eens212/metamorphreact.htm

|title=Types of Metamorphic Reactions

|publisher=Tulane University

|accessdate=2007-06-22

}}

Examples include the production of talc under varied metamorphic conditions:

:serpentine + carbon dioxide → talc + magnesite + water

:chlorite + quartz → kyanite + talc + water

File:Epidotisation - geograph.org.uk - 2979796.jpg, U.K]]