Most of the minerals in nature are crystals, and a small number are amorphous.

Basic properties of crystals: Self-limiting: It has the characteristic of spontaneously forming closed geometric polyhedrons. Symmetry: The regular recurrence of equal crystal faces, edges, and vertices. Uniformity: The macroscopic properties of all internal parts are the same. Anisotropy: Different physical properties in different directions. Stability: Compared with amorphous, liquid, and gaseous substances of the same kind, it has the smallest internal energy

Mineral monomer form refers to the form of mineral single crystal. Only crystalline minerals can appear in monomer form.

Monotypic: Crystals composed of crystal faces of the same type and size (47 types)

Polymorphism: crystal faces of different shapes, sizes, and many types

Crystal habit: The characteristic of the same mineral crystal tending to a certain form under certain external conditions.

Self-color: a color whose origin is directly related to the inherent chemical composition of the mineral itself Other colors: caused by factors other than those inherent in the mineral itself, such as impurities, impurity elements, and crystal defects. False color: caused by physical optical processes such as light interference and diffraction

Conchoidal fracture is a rounded smooth surface with irregular concentric stripes often appearing on the surface, resembling a shell, such as quartz and vitreous.

Jagged fractures are sharply jagged. Very ductile minerals have such fractures, such as natural copper.

Jagged fracture is uneven and rough. Most minerals have such fractures, such as apatite.

Chemical composition is divided into major categories and classes Crystal structure classification families An independent unit with a certain structure and certain components is a species.