Read the dictionary definition of crystal. All definitions for this word.
1. a protective cover that protects the face of a watch
2. glassware made of quartz
3. a crystalline element used as a component in various electronic devices
4. a rock formed by the solidification of a substance; has regularly repeating internal structure; external plane faces
5. colorless glass made of almost pure silica
6. a solid formed by the solidification of a chemical and having a highly regular atomic structure