micaserpentine

Micaserpentine is a descriptive term used in geology to refer to a rock or rock assemblage in which serpentine minerals occur alongside mica minerals, typically muscovite or phlogopite. It is not a recognized mineral species but rather a textural or compositional descriptor applied to serpentine-rich rocks that contain notable amounts of sheet silicates in addition to serpentine.

Composition and textures

The core of micaserpentine is serpentine, a group of hydrous magnesium-iron silicates (including antigorite, lizardite, and chrysotile). Intergrown with or overlain by mica minerals, especially white mica varieties such as muscovite or phlogopite, the rock displays a lamellar or foliate texture characteristic of phyllosilicates. Accessory minerals may include chlorite, talc, magnetite, and carbonate minerals, depending on the metamorphic history and fluid conditions.

Formation and environment

Micaserpentine forms through hydrothermal alteration or low- to moderate-grade metamorphism of ultramafic rocks under mantle-derived fluids. Serpentinization and subsequent phyllosilicate mineral growth can occur in subduction zones or ultramafic belts, where fluids facilitate mica crystallization alongside serpentine.

Properties and occurrence

Color is typically green to brown, with a soft feel (serpentine hardness) and a pearly to silky luster from the mica. Micaserpentine is most often described in regional studies of ophiolites or serpentine belts rather than as a distinct, widely catalogued rock type.

Uses and significance

Due to its decorative potential and its association with serpentine alteration, micaserpentine may be noted in mineralogical surveys and can appear in ornamental stone contexts. If chrysotile is present, health and safety considerations related to asbestos-bearing materials may apply.

See also

Serpentine, serpentinization, mica, muscovite, phlogopite, serpentinite.