sericite

{{Short description|Aggregates of micas}}

{{distinguish|Cerussite|lead carbonate}}

Image:Mineraly.sk - sericit.jpg

Sericite is the name given to very fine, ragged grains and aggregates of white (colourless) micas, typically made of muscovite, illite, or paragonite.{{cite book|last1=Nesse|first1=William D.|title=Introduction to mineralogy|date=2012|publisher=Oxford University Press|location=New York|isbn=978-0199827381|edition=2nd}} Sericite is produced by the alteration of orthoclase or plagioclase feldspars in areas that have been subjected to hydrothermal alteration (also see Sericitic 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.

The name comes 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.

File:Granite pmg ss 2006.jpg|Granite in thin section under cross-polarized light in which feldspar crystals exhibit sericite alteration

File:Staurolite garnet schist 3mm xp 2007.jpg|Staurolite-garnet schist in thin section under cross-polarized light with sericite