Serpentine subgroup

The serpentine subgroup comprises 1:1 layer silicate minerals built from linked tetrahedral silica and octahedral brucite-like sheets. Its principal members are antigorite, chrysotile, and lizardite.

Phyllosilicate: A silicate mineral with structures organized into sheets of linked tetrahedra and octahedra. Serpentine minerals belong to this broad sheet-silicate family.
Antigorite: A serpentine mineral with periodically modulated layers, commonly forming platy or bladed crystals. Its layer modulation accommodates structural mismatch without forming tubes.
Serpentinization: The hydration and alteration of ultramafic rocks, producing serpentine minerals and commonly other phases. This process produces much of the serpentine found in nature.
Serpentinite: A rock composed largely of serpentine minerals, commonly formed by alteration of ultramafic rocks. It is the rock-scale expression of abundant serpentine minerals.
1:1 layer silicate: A phyllosilicate layer made of one tetrahedral sheet joined to one octahedral sheet. This layer architecture defines the subgroup’s structure.
Chrysotile: A fibrous serpentine mineral whose rolled layers form hollow cylindrical structures. Curvature rolls its layers into fibers and tubes.
Peridotite: A coarse-grained ultramafic igneous rock composed mainly of olivine and pyroxene. Peridotite is a common precursor rock for serpentine formation.
Asbestos: A group of naturally occurring fibrous silicate minerals regulated for their health hazards. Chrysotile is an asbestos mineral and has a distinct exposure history.
Silica tetrahedron: A silicon atom surrounded by four oxygen atoms in a tetrahedral arrangement. These tetrahedra form the silica sheet in serpentine layers.
Lizardite: A serpentine mineral with relatively flat, often platy layers. Its comparatively uncurved layers contrast with tubular chrysotile.

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Chlorite groupCompared with: Serpentine minerals often form in similar rocks but have a different layer arrangement.