Kristály

Kristály is the Hungarian term for crystal. In crystallography and mineralogy, a crystal is a solid material whose constituents—atoms, ions, or molecules—are arranged in a highly ordered, repeating pattern that extends in all directions. This orderly arrangement gives crystals characteristic external surfaces and angles.

Crystals form when a substance solidifies from a melt, solution, or vapor, allowing its internal order to develop. Growth conditions such as temperature, pressure, concentration, and the presence of impurities influence size, shape, and quality. Crystals occur naturally in minerals and rocks and can be grown synthetically in laboratories.

The internal arrangement is described by a crystal lattice and the smallest repeating unit, the unit cell. Crystals are grouped into seven crystal systems (cubic, tetragonal, orthorhombic, hexagonal, trigonal, monoclinic, triclinic) based on lattice parameters, and 14 Bravais lattices describe lattice centering in three dimensions. Crystal habit and cleavage affect appearance and breakage.

Crystals range from pure substances to compounds. Ionic crystals include halite (sodium chloride); covalent crystals include diamond, while quartz has a framework of silicon-oxygen bonds; metallic crystals form in metals such as copper. Commonly observed properties include hardness, transparency, and birefringence, as well as phenomena like piezoelectricity in certain minerals.

Crystals are integral to technology and industry. Quartz crystals regulate time in watches and electronics; halite provides edible salt; ice crystals form in frost; gemstones are valued for optical properties. Crystallography underpins material science, geology, chemistry, and solid-state physics.