Sericite

Named in 1852 from Latin sericus, meaning "silken" in reference to the location from which silk was first utilized, which in turn refers to the silky sheen of rocks with abundant sericite. Sericite is a common alteration mineral of orthoclase or plagioclase feldspars in areas that have been subjected to hydrothermal alteration typically associated with copper, tin, or other hydrothermal ore deposits. Sericite also occurs as the fine mica that gives the sheen to phyllite and schistose metamorphic rocks.

Bibliography

• Cox et al. (1979): The Interpretation of Igneous Rocks, George Allen and Unwin, London.
• Howie, R. A., Zussman, J., & Deer, W. (1992). An introduction to the rock-forming minerals (p. 696). Longman.
• Le Maitre, R. W., Streckeisen, A., Zanettin, B., Le Bas, M. J., Bonin, B., Bateman, P., & Lameyre, J. (2002). Igneous rocks. A classification and glossary of terms, 2. Cambridge University Press.
• Middlemost, E. A. (1986). Magmas and magmatic rocks: an introduction to igneous petrology.
• Shelley, D. (1993). Igneous and metamorphic rocks under the microscope: classification, textures, microstructures and mineral preferred-orientations.
• Vernon, R. H. & Clarke, G. L. (2008): Principles of Metamorphic Petrology. Cambridge University Press.

Photo
Feldspars altered by sericite in a hydrothermal altered Dacite. XPL image, 2x (Field of view = 7mm)	Feldspars altered by sericite in a hydrothermal altered Dacite. XPL image, 2x (Field of view = 7mm)	Feldspars altered by sericite in a hydrothermal altered Dacite. XPL image, 10x (Field of view = 2mm)
Feldspars altered by sericite in a hydrothermal altered Dacite. XPL image, 10x (Field of view = 2mm)	Feldspars altered by sericite in a hydrothermal altered Dacite. XPL image, 10x (Field of view = 2mm)	Feldspars altered by sericite in a hydrothermal altered Dacite. XPL image, 10x (Field of view = 2mm)
Feldspars altered by sericite in a hydrothermal altered Dacite. XPL image, 10x (Field of view = 2mm)	Feldspars altered by sericite in a hydrothermal altered Dacite. XPL image, 10x (Field of view = 2mm)	Feldspars altered by sericite in a hydrothermal altered Dacite. XPL image, 10x (Field of view = 2mm)
Feldspars altered by sericite in a hydrothermal altered Dacite. XPL image, 10x (Field of view = 2mm)	Feldspars altered by sericite in a hydrothermal altered Dacite. XPL image, 10x (Field of view = 2mm)	Feldspars altered by sericite in a hydrothermal altered Dacite. XPL image, 10x (Field of view = 2mm)
Plagioclase altered by sericite in a hydrothermal altered Dacite. XPL image, 10x (Field of view = 2mm)	Plagioclase altered by sericite in a hydrothermal altered Dacite. XPL image, 10x (Field of view = 2mm)	Plagioclase altered by sericite in a hydrothermal altered Dacite. XPL image, 10x (Field of view = 2mm)