plagioclase
noun
pla·gio·clase
ˈplā-j(ē-)ə-ˌklās 
ˈpla-,
-ˌklāz
: a triclinic feldspar
especially
: one having calcium or sodium in its composition
Examples of plagioclase in a Sentence
Recent Examples on the Web
Additionally, the meteorites both contain only trace amounts of the mineral plagioclase, which is thought to make up over 37 percent of Mercury’s surface.
—
Sara Hashemi, Smithsonian Magazine, 17 July 2025
Several apatite grains are observable in the margins of plagioclase and pyroxene (Supplementary Fig. 3).
—Keith Cooper, Space.com, 16 July 2025
However, the meteorites contained only trace amounts of plagioclase, a mineral believed to dominate Mercury’s surface.
—Jacopo Prisco, CNN Money, 14 July 2025
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
The countertop has quartz, plagioclase feldspar, potassium feldspar and biotite?
—Erik Klemetti, Discover Magazine, 25 Mar. 2025
So, take something like plagioclase, pyroxene and olivine, the most abundant minerals in basalt and all anhydrous (lacking water in their structure) and plop it for thousands to millions of years in a wet environment like an ocean floor.
—Erik Klemetti, Discover Magazine, 27 June 2024
The Alaska Volcano Observatory has posted some great images of the the ash (see above) collected from the Veniaminof eruption, including some that show the glassy shards with blades of plagioclase (microlites) in the volcanic glass.
—Erik Klemetti, Discover Magazine, 23 Sep. 2013
Changing chemical composition of the magma can betray the rapid crystallization of the mineral plagioclase feldspar.
—Erik Klemetti, Discover Magazine, 14 Nov. 2018
Examples are automatically compiled from online sources to
show current usage.
Read More
Opinions expressed in the examples do not represent those of Merriam-Webster or its editors.
Send us feedback.
Sara Hashemi, Smithsonian Magazine, 17 July 2025
Several apatite grains are observable in the margins of plagioclase and pyroxene (Supplementary Fig. 3).
—Keith Cooper, Space.com, 16 July 2025
However, the meteorites contained only trace amounts of plagioclase, a mineral believed to dominate Mercury’s surface.
—Jacopo Prisco, CNN Money, 14 July 2025
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
The countertop has quartz, plagioclase feldspar, potassium feldspar and biotite?
—Erik Klemetti, Discover Magazine, 25 Mar. 2025
So, take something like plagioclase, pyroxene and olivine, the most abundant minerals in basalt and all anhydrous (lacking water in their structure) and plop it for thousands to millions of years in a wet environment like an ocean floor.
—Erik Klemetti, Discover Magazine, 27 June 2024
The Alaska Volcano Observatory has posted some great images of the the ash (see above) collected from the Veniaminof eruption, including some that show the glassy shards with blades of plagioclase (microlites) in the volcanic glass.
—Erik Klemetti, Discover Magazine, 23 Sep. 2013
Changing chemical composition of the magma can betray the rapid crystallization of the mineral plagioclase feldspar.
—Erik Klemetti, Discover Magazine, 14 Nov. 2018
Cite this Entry
“Plagioclase.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/plagioclase. Accessed 26 Jul. 2025.
Copy CitationLove words? Need even more definitions?
Merriam-Webster unabridged
Share