perimorph
/ˈpɛrɪmɔːrf/
noun
- A mineral crystal that forms a shell or outer layer around another mineral or crystal.
- In the rock sample, the perimorph had completely enclosed the inner crystal.
- Collectors value perimorphs for their unusual layered structure.
- The geologist identified a perimorph of quartz surrounding a core of calcite.
Antonyms