a protective cover that protects the face of a watch | sand that is mainly composed of quartz, used as the main raw material for commercial glass production. |
glassware made of quartz | |
a crystalline element used as a component in various electronic devices | |
a rock formed by the solidification of a substance; has regularly repeating internal structure; external plane faces | |
a solid formed by the solidification of a chemical and having a highly regular atomic structure | |
colorless glass made of almost pure silica | |