microclinerich

Microclinerich is a geological term used to describe rocks or soils that have a relatively high modal content of microcline, a form of alkali feldspar (potassium feldspar) with the chemical composition KAlSi3O8. The designation emphasizes the dominance of microcline within the mineral assemblage, as opposed to rocks where plagioclase or other feldspars are more abundant.

Microcline is typically stable in felsic to intermediate rocks and forms during late-stage crystallization of granitic magmas and in pegmatites. Consequently, microclinerich rocks are often coarse-grained and may occur within granitoids, granitic xenoliths, or associated pegmatitic bodies. Their presence can influence the texture and weathering behavior of the rock and may be used to infer magmatic history and crystallization conditions.

Identification and analysis are usually carried out through petrographic examination of hand samples and thin sections, complemented by mineralogical dating and modal analysis. In hand specimens, microcline can contribute pink to salmon hues and may be distinguished by its cleavage and crystal habits in cross-polio observations. Quantitative assessment commonly relies on X-ray diffraction or electron microprobe analysis to determine the exact proportion of microcline relative to other feldspars and minerals.

The term microclinerich is not universally standardized and may be used interchangeably with phrases like microcline-rich, depending on regional or disciplinary preferences. It is primarily of interest in petrology and mineralogy for characterizing rock textures, provenance, and magmatic evolution. See also microcline, alkali feldspar, granitoid, pegmatite, and granite.