Kristalklassificatie

Kristalklassificatie is the systematic division of crystalline solids based on their internal geometrical and symmetry properties. It is the foundation of mineralogy, crystallography and materials science, allowing scientists to categorize crystals according to how their atoms are arranged in three dimensions. The most common basis for classification is the crystal system, which is defined by the lengths of the unit cell edges and the angles between them. There are seven crystal systems: cubic (isometric), tetragonal, orthorhombic, hexagonal, trigonal, monoclinic and triclinic. Within each system are crystal classes that are distinguished by their point group symmetries; there are 32 crystallographic point groups. The complete symmetry of a crystal is ultimately described by one of 230 distinct space groups, which combine translational symmetry of the lattice with point-group operations.

Historically, early classifications combined external crystal habits with internal structures; pioneers such as Wollaston’s 1817 catalogue began to distinguish minerals by external form, while Alfred Stenhouse and later Hermann Maier-Abegg in the late 1800s laid the groundwork for systematic lattice-based taxonomy. Modern crystallography uses X‑ray diffraction to derive lattice parameters and symmetry elements, enabling precise placement of a specimen within the appropriate crystal class and space group. Kristalklassificatie is essential for determining mineral identity, predicting physical properties, and interpreting geological processes such as metamorphism and crystal growth.