noun
- plural of plagioclase; a group of feldspar minerals that are common rock-forming silicates containing sodium and calcium
Usage: geology; mineralogy
Examples
- The granite sample contained several different plagioclases.
- Plagioclases are among the most abundant minerals in the Earth’s crust.
- The geologist identified various plagioclases in the volcanic rock.
- These plagioclases formed during the slow cooling of magma.
- The composition of plagioclases varies from sodium-rich to calcium-rich varieties.
- Students learned to distinguish plagioclases from other feldspars under the microscope.