Formula: Mg2Al(AlSiO5)(OH)4
Phyllosilicate (sheet silicate), serpentine subgroup
Crystal System: Triclinic
Specific gravity: 2.77 to 2.78 measured, 2.7 calculated
Hardness: 2½ to 3
Streak: White with very pale green tint
Colour: Originally pale greyish blue-green, also white, colourless, pale green, pink to lilac (chromian)

Metamorphic environments

Amesite is a product of low-grade metamorphism of rocks rich in aluminium and manganese (Webmin). It is found with clinochlore and magnetite, sometimes with grossular, diopside, calcite and clinozoisite, and occasionally with margarite; it occurs rarely as an alteration product of cancrinite (Dana).

At the Pensacola Mountains, Antarctica, amesite is associated with vesuvianite and chlorite (HOM).

At Mine Lac d'Amiante (Lake Asbestos Mine; "LAB Mine"; "Black Lake Mine"), Saint-Joseph-de-Coleraine, Les Appalaches RCM, Chaudière-Appalaches, Quebec, Canada, iron-rich amesite is found in a metasomatically altered granite sheet emplaced in serpentinite. The amesite is associated with a rodingite assemblage (grossular + calcite +/- diopside +/- clinozoisite) that has replaced the primary minerals of the granite. The Quebec amesite occurs as subhedral grains 200 to 600 microns in diameter that have a tabular habit. It formed during hydrothermal alteration of granite in serpentinite at the same low P-T conditions that prevailed during the formation of the rodingite suite and the chrysotile asbestos in the serpentinite (CM 22.3.437–442).

At Mount Sobotka, lower Silesia, Poland, amesite occurs with a variety of chlorite in vesicles in rock fragments in the soils derived from a serpentinite (AM 76.647-652).

At the type locality, the Chester Emery Mines, Chester, Hampden county, Massachusetts, USA, amesite occurs in an emery deposit associated with rutile, magnetite, diaspore, clinochlore (Mindat, HOM) and chamosite (AM 29.422-430).

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