feldspar

noun

feld·​spar ˈfel(d)-ˌspär 

: any of a group of crystalline minerals that consist of aluminum silicates with either potassium, sodium, calcium, or barium and that are an essential constituent of nearly all crystalline rocks

Examples of feldspar in a Sentence

Recent Examples on the Web

Through their research, the team has discovered two types of mineral-rich volcanic rocks: a dark rock with iron, magnesium, pyroxene and plagioclase feldspar, as well as a light-toned trachyandesite with plagioclase crystals and potassium. —Stefanie Waldek, Space.com, 18 Apr. 2025

Large plagioclase feldspar crystals can be seen below the hornblende, all embedded in a matrix of volcanic glass and feldspar crystals. —Erik Klemetti, Discover Magazine, 25 Mar. 2025

The countertop has quartz, plagioclase feldspar, potassium feldspar and biotite? —Erik Klemetti, Discover Magazine, 25 Mar. 2025

The island's copper and feldspar deposits also offer plenty for myriad industries and the construction sector. —Gaurav Sharma, Forbes, 8 Jan. 2025

Word History

Etymology

modification of obsolete German Feldspath (now Feldspat), from German Feld field + obsolete German Spath (now Spat) spar

First Known Use

1772, in the meaning defined above

Rhymes for feldspar

• adar
• afar
• ajar
• alar
• ansar
• bazaar
• bizarre
• boxcar
• boyar
• bulbar
• cachar
• cigar

Kids Definition

feldspar

noun

feld·​spar ˈfel(d)-ˌspär 

: any of a group of crystalline minerals that consist of silicates of aluminum with potassium, sodium, calcium, or barium and that are a basic part of nearly all crystalline rocks