glauconite
/ˈɡlɔːkənaɪt/
noun
- A greenish mineral found in sedimentary rocks, often used as a fertilizer and in water softening.
- Farmers sometimes add glauconite to soil to improve its potassium content.
- The green sand on that beach gets its color from tiny grains of glauconite.
- Geologists study glauconite to learn about ancient ocean environments.