Serpentine subgroup

rock-forming hydrous magnesium iron phyllosilicate

right|thumb|Serpentinite from the Maurienne valley, [[Savoie, French Alps]] right|thumb|Sample of serpentinite from the Golden Gate National Recreation Area, California, United States thumb|Chromite|Chromitic serpentinite ( across), [[Styria Province, Austria. Protolith was a Proterozoic-Early Paleozoic upper mantle dunite peridotite that has been multiply metamorphosed during the Devonian, Permian, and Mesozoic.]] thumb|Tightly folded serpentinite from the Tux Alps, [[Austria. Closeup view about .]]

Chrysotile (/ˈkrɪsəˌtʌɪl/, /ˈkrɪsəˌtaɪl/, or /ˈkrɪsətɪl/) or white asbestos is the most commonly encountered form of asbestos, accounting for approximately 95% of the asbestos in the United States and a similar proportion in other countries. It is a soft, fibrous silicate mineral in the serpentine subgroup of phyllosilicates; as such, it is distinct from other asbestiform minerals in the amphibole group. Its idealized chemical formula is Mg(SiO)(OH). The material has physical properties which make it desirable for inclusion in building materials, but poses serious health risks when dispersed i

Antigorite is a lamellated, monoclinic mineral in the phyllosilicate serpentine subgroup with the ideal chemical formula of (Mg,Fe2+)3Si2O5(OH)4. It is the high-pressure polymorph of serpentine and is commonly found in metamorphosed serpentinites. Antigorite, and its serpentine polymorphs, play an important role in subduction zone dynamics due to their relative weakness and high weight percent of water (up to 13 weight % H2O). It is named after its type locality, the Geisspfad serpentinite, Valle Antigorio in the border region of Italy/Switzerland and is commonly used as a gemstone in jewelry

Amesite is a mineral with general formula of Mg2Al2SiO5(OH)4.

Lizardite is a mineral from the serpentine subgroup with formula , and the most common type of mineral in the subgroup. It is also a member of the kaolinite-serpentine group.

Cronstedtite is a complex iron silicate mineral belonging to the serpentine group of minerals. Its chemical formula is .

Népouite is a rare nickel silicate mineral which has the apple green color typical of such compounds. It was named by the French mining engineer Edouard Glasser in 1907 after the place where it was first described (the type locality), the Népoui Mine, , Poya Commune, North Province, New Caledonia. The ideal formula is , but most specimens contain some magnesium, and is more realistic. There is a similar mineral called lizardite (named after the Lizard Complex in Cornwall, England) in which all of the nickel is replaced by magnesium, formula . These two minerals form a series; intermediate comp

Fraipontite is a zinc aluminium silicate mineral with a formula of .

Pecoraite is a nickel silicate mineral and a member of the serpentine group. It was named after geologist William Thomas Pecora. It is monoclinic and has a chemical composition of . It is associated with the weathering-and-or oxidation of meteorites or nickel sulfide minerals such as millerite. It is also found in altered ultramafic rocks. Pecoraite is typically a green, lime green, or bluegreen mineral with a waxy, or earthy luster and a mohs hardness of 2.5. Common textural habits associated with pecoraite are curved plates, spirals and tubes. It can also be granular and massive.

Caryopilite (synonymous with ectropite and ektropite) is a brown-colored mineral with formula (Mn2+,Mg)3Si2O5(OH)4. The mineral was discovered in 1889 from a mine in Sweden. It was named for the Greek words for walnut and felt in reference to its appearance.