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

Different colors of sand come from different minerals, like khaki feldspar, smoky white quartz, green olivine or black basalt. —David R. Montgomery, Discover Magazine, 12 July 2024

This happens when light scatters between microscopic layers of feldspar in the gem, the Geological Institute of America reports. —Olivia Munson, USA TODAY, 18 June 2024

With their distinctive bands and sporadic veins of quartz and feldspar, the stones sparkle whenever sunlight strikes them. —Dan Falk, Discover Magazine, 6 Apr. 2024

In the lab, the researchers then peered inside individual sand grain crystals of quartz and feldspar to measure environmental radiation that accumulated over thousands of years in the dune’s dark depths. —Mindy Weisberger, CNN, 4 Mar. 2024

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

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