ETYM Old Eng. cristal, French cristal, Latin crystallum crystal, ice, from Greek krystallos, from kryos icy cold, frost; cf. AS. crystalla, from Latin crystallum; prob. akin to Eng. crust. Related to Crust, Raw.
1. A crystalline element used in various electronic devices.
2. A protective cover that protects the face of a watch; SYN. watch crystal, watch glass.
3. A rock formed by the solidification of a substance; has regularly repeating internal structure; external plane faces.
4. A solid formed by the solidification of a chemical and having a highly regular atomic structure.
5. Glassware made of quartz.
Substance with an orderly three-dimensional arrangement of its atoms or molecules, thereby creating an external surface of clearly defined smooth faces having characteristic angles between them. Examples are table salt and quartz.
Each geometrical form, many of which may be combined in one crystal, consists of two or more faces—for example, dome, prism, and pyramid. A mineral can often be identified by the shape of its crystals and the system of crystallization determined. A single crystal can vary in size from a submicroscopic particle to a mass some 30 m/100 ft in length. Crystals fall into seven crystal systems or groups, classified on the basis of the relationship of three or four imaginary axes that intersect at the center of any perfect, undistorted crystal.
Three common crystalline forms are: (1) the simple cubic structure of ionic crystals, such as those of sodium chloride (NaCl); (2) the face-centered cubic structure of metals such as aluminum, copper, gold, silver, and lead; and (3) the hexagonal close-packed structure of metals such as cadmium and zinc. + prikaži više