hydrogarnet

Hydrogarnet refers to a group of minerals belonging to the garnet supergroup that contain structural water. Unlike most garnets which have the general formula X3Y2(SiO4)3, hydrogarnets incorporate hydroxyl groups (OH) or water molecules (H2O) into their crystal structure. The presence of water can lead to variations in their physical and chemical properties compared to anhydrous garnets.

These minerals are often found in environments where water is abundant during their formation, such as in metamorphic rocks that have undergone hydrothermal alteration or in certain types of igneous rocks. The incorporation of water can affect the garnet's refractive index, density, and hardness. Hydrogarnets can exhibit a range of compositions, often substituting for silicon or other elements within the silicate tetrahedra.

Examples of hydrogarnets include minerals like kyanite-bearing hydrogrossular and grossular-garnet with significant OH substitution. Their geological significance lies in their role as indicators of metamorphic conditions and fluid activity. Studying hydrogarnets helps geologists understand the processes of mineral formation and alteration in the Earth's crust. Research on hydrogarnets also contributes to understanding the behavior of water within mineral structures, which has implications for various scientific fields, including materials science and planetary geology.