plagioclase
/ˈpleɪdʒiəˌkleɪs/
noun
- A common type of mineral found in many rocks, usually white or gray, that is an important part of the Earth's crust.
- Under a microscope, plagioclase shows fine parallel lines on its surface.
- Plagioclase is often found in volcanic rocks like basalt.
- The geologist identified plagioclase in the granite sample.