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LITHOEN

Mineral group

Feldspar

The most abundant mineral group of the crust — and a group, not a species. Its members split into the plagioclase series and the alkali feldspars, three of which share one formula and differ only in structural order.

A cut and polished granite surface showing interlocking pale and dark crystals a few millimetres across.
A granite from the Kösseine massif, Germany. The interlocking crystals of quartz, feldspar and mica are visible without magnification — the coarse texture that records slow cooling at depth. Locality: Kösseine, Bavaria, Germany.

Georgenhausen, CC BY-SA 4.0 · CC-BY-SA-4.0 · source · Derivative: Downscaled to 1000 px wide by the Wikimedia thumbnail service; no cropping, no colour or content alteration.

Classification

group kind
group

How this record is known

2
Settled consensus
Cited as the accepted position of the discipline.

2 of 2 claims on this page cite at least one registered source. Counts describe how each statement is known, not how likely it is to be true.

What Lithoen records

Each claim states how it is known and cites its evidence.

EstablishedGroup names are used as mineral names in ordinary scientific writing, including by primary authorities.

Authoritative sources routinely use group names as though they were minerals: the USGS lists quartz, feldspar, mica, amphibole, olivine and calcite together as “common minerals”, although only quartz and calcite among those are accepted species.

  • precision note: Recorded as a fact about usage, not as an error to be corrected in the source. Both usages are legitimate in their own register; conflating them in a database is not.

Evidence support: Supported by the cited evidence 2 sources, multiple sources, independence unknown

Evidence: U.S. Geological Survey n.d. Primary authority; Commission on New Minerals, Nomenclature and Classification, International Mineralogical Association 2026 Primary authority

EstablishedNot a species; a group.

“Feldspar” is not an accepted mineral species: no entry of that name appears in the IMA List of Minerals. It denotes a group comprising the plagioclase series and the alkali feldspars.

  • definition basis: Absence from the IMA List of Minerals, which is the list of accepted species.
  • precision note: The name remains in ordinary scientific use. It is recorded as a grouping so that it stays usable without being mistaken for a species.

Evidence support: Supported by the cited evidence one source

Evidence: Commission on New Minerals, Nomenclature and Classification, International Mineralogical Association 2026 Primary authority

In the knowledge graph

Record last updated 2026-09-06. Corrections follow the published corrections policy; superseded claims are retained, never silently edited.