Micrite

Micrite is a limestone constituent formed of calcareous particles ranging in diameter up to four μm formed by the recrystallization of lime mud.
Micrite is lime mud, carbonate of mud grade. In the Folk classification micrite is a carbonate rock dominated by fine-grained calcite. Carbonate rocks that contain fine-grained calcite in addition to allochems are named "intramicrite", "oomicrite", "biomicrite" or "pelmicrite" under the Folk classification depending on the dominant allochem.
Micrite as a component of carbonate rocks can occur as a matrix, as micrite envelopes around allochems or as peloids.
Micrite can be generated by chemical precipitation, from disaggregation of peloids, or by micritization.
The term was coined in 1959 by Robert Folk for his carbonate rock classification system. Micrite is derived from MICRocrystalline calcITE.