What does felspar mean?
Felspar is a British spelling of feldspar, the name given to one of the most abundant mineral groups on Earth. Felspars are aluminium silicate minerals — including orthoclase, albite, and labradorite — that form a major constituent of igneous rocks such as granite, as well as many metamorphic and sedimentary rocks. They are prized industrially as fluxes in ceramics and glassmaking and are familiar to collectors for crystals that range from milky white to salmon pink and even iridescent blue. The word entered English in the eighteenth century from German Feldspath, literally 'field spar', where 'spar' is an old miners' term for readily cleaved, non-metallic minerals. Today 'felspar' survives largely as a British, somewhat traditional spelling, while 'feldspar' predominates internationally and in scientific writing. Encountering the term usually signals a discussion of geology, petrology, stoneware, or gemstones, and knowing it marks the reader as conversant with the basic vocabulary of the solid Earth.
nounFelspar is a British spelling of feldspar, referring to any of a group of abundant rock-forming aluminium silicate minerals that make up a large proportion of the Earth's crust, including orthoclase, albite, and labradorite.
- Any of a group of rock-forming aluminium silicate minerals (such as orthoclase, albite, and labradorite) that constitute a major component of igneous, metamorphic, and sedimentary rocks.
"The granite outcrop glittered in the sunlight, its pink crystals of felspar catching the eye from across the valley."
"The potter selected a clay rich in felspar because it would act as a natural flux during firing."
"Under the geologist's lens, the thin section revealed interlocking grains of quartz and felspar."
Used when referring to different members or varieties of the mineral group collectively.
"The pegmatite contained large crystals of quartz, mica, and several distinct felspars."
This mineral makes up roughly half of the Earth's crust — yet most people can't even settle on how to spell it.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of felspar
Felspar derives from the German Feldspath, a compound of Feld ('field') and Spath (or Spar), an old miners' word for non-metallic minerals that break into smooth plates. The term was adopted into English in the eighteenth century, where the German spelling was anglicised variously as 'feldspar' and 'felspar'. Both spellings refer identically to the same mineral group; the shortened 'fels-' form became established chiefly in British usage, while 'feldspar' ultimately prevailed in international scientific nomenclature.
Related word forms
How felspar is actually used
The spelling 'felspar' is chiefly British and now somewhat dated; 'feldspar' has become the dominant form in scientific literature worldwide. As a technical mineralogical term, it appears mainly in formal, geological, or lapidary contexts rather than everyday speech.
Easily confused with felspar
'Feldspar' is the standard spelling in both American and modern international usage, while 'felspar' is an older British spelling of exactly the same mineral group.