Answer:
Mineral hydration.
Step-by-step explanation:
Mineral hydration is a chemical reaction where water is added to the crystal structure of a mineral, usually creating a new mineral sometimes called a hydrate. The process called mineral hydration is known as retrograde alteration and is a process occurring in retrograde metamorphism.
Examples are: Silicates - Chlorites and Non-sillicates - Carbonates, oxides etc.