mineral

Introduction
Definition
Nomenclature
Occurrence and formation
The nature of minerals
- Morphology
  - Symmetry elements
  - Twinning
- Internal structure
  - Examining crystal structures
  - Space groups
  - Illustrating crystal structures
- Polymorphism
- Chemical composition
- Mineral formulas
- Compositional variation
- Chemical bonding
  - Ionic bonds
  - Covalent bonds
  - Metallic bonds
  - Van der Waals bonds
  - Hydrogen bonds
- Physical properties
  - Crystal habit and crystal aggregation
  - Cleavage and fracture
  - Lustre
  - Colour
  - Hardness
  - Tenacity
  - Specific gravity
  - Magnetism
  - Fluorescence
  - Solubility in hydrochloric acid
  - Radioactivity
Classification of minerals
- Native elements
  - Metals
  - Semimetals
  - Nonmetals
- Sulfides
- Sulfosalts
- Oxides and hydroxides
- Halides
- Carbonates
- Nitrates
- Borates
- Sulfates
- Phosphates
- Silicates
  - Nesosilicates
  - Sorosilicates
  - Cyclosilicates
  - Inosilicates
  - Phyllosilicates
  - Tectosilicates
Mineral associations and phase equilibrium
- Assemblage and the phase rule
- Phase diagrams
  - Use in igneous petrology
  - Use in metamorphic petrology
  - Use in sedimentary petrology

References & Edit History Related Topics

Images & Videos

A vivid blue, textured mineral specimen of azurite displayed against a pale purple background.

A schematic diagram shows the cubic crystal structure of pyrite, FeS2, with blue spheres representing ferrous iron cations (Fe2+) and yellow spheres representing sulfur anions (S-) arranged in a three-dimensional grid.

A cluster of pyrite crystals with a metallic gold appearance is shown, featuring both pentagonal dodecahedron shapes and striated cubic forms. Insets highlight the detailed structure of a pentagonal dodecahedron and a striated pyrite cube, with labels explaining their geometric outlines and the mineral's composition of iron and sulfur ions.

Diagram showing four types of translation-free symmetry in crystals: a sixfold axis of rotation, a fourfold axis of inversion, a center of symmetry, and a mirror plane, each illustrated with a labeled purple crystal shape and explanatory text.

Three illustrated crystals are shown to demonstrate different crystal classes and symmetries: a tall, prismatic monoclinic gypsum crystal; a pointed, double-ended tetragonal wulfenite crystal; and a cubic isometric halite crystal, each labeled with its crystal class and symmetry content.

What Are the Seven Basic Crystal Systems?

At a Glance

A clear, faceted quartz crystal with sharp edges and a pointed tip is displayed against a dark blue fabric background.

mineral summary

mineral

chemical compound

Written by

Cornelis Klein

Fact-checked by

Britannica Editors

Last updated

Oct. 29, 2026 •History

mineral, naturally occurring homogeneous solid with a definite chemical composition and a highly ordered atomic arrangement; it is usually formed by inorganic processes. There are several thousand known mineral species, about 100 of which constitute the major mineral components of rocks; these are the so-called rock-forming minerals. A mineral, which by definition must be formed through natural processes, is distinct from the synthetic equivalents produced in the laboratory. Artificial versions of minerals, including emeralds, sapphires,...

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