spherulite
/ˈsfɛr.jə.laɪt/
noun
- A small, rounded mass of crystals that forms in some types of rock, especially volcanic glass, often looking like a tiny ball or sphere.
- The geologist explained that each spherulite formed when the lava cooled very quickly.
- Hikers sometimes find spherulites in obsidian, where they look like small, dark spots in the shiny black rock.
- Under the microscope, the spherulite appeared as a beautiful, radiating cluster of needle-like crystals.