Minerals are natural solid, inorganic substances (with a few exceptions), which have a defined chemical composition and a specific crystal structure. They are classified according to different criteria such as their chemical composition, crystal structure and physical properties. This classification allows geologists and mineralogists to better understand and organize the 5663 mineral species present in nature.

The most commonly used method for classifying minerals is based on their chemical composition. This classification is based on the predominant anion or anionic group in the mineral. Minerals are thus divided into several classes according to their dominant elements. Here are the main mineralogical classes according to the chemical classification :

• Native elements
• Sulfides and sulfosalts
• Halides
• Oxides and hydroxides
• Carbonates, nitrates, borates, iodates
• Sulfates, chromates, molybdates, tungstates
• Phosphates, arsenates, vanadates
• Silicates
• Organic compounds

In addition to their chemical composition, minerals are classified according to their crystalline structure, that is, the way their atoms or ions are organized in space. This approach is crucial to understanding the physical properties of minerals, because the crystalline form influences characteristics such as hardness, cleavage, and luster.

There are seven main crystal systems, which describe all the geometric shapes of crystals :

• Cubic (or isometric) system
• Hexagonal system
• Tetragonal system
• Trigonal system
• Orthorhombic system
• Monoclinic system
• Triclinic system

There are two mineral classification systems widely used by mineralogists :

Dana classification : Developed by American geologist James Dwight Dana in 1837, this method classifies minerals according to their chemical groups, based mainly on anions or anionic groups, such as silicates, carbonates, sulfates, etc... Within these groups, minerals are further subdivided according to their crystal structure and physical properties. Each mineral is assigned a unique number in a specific sequence that reflects its chemical group, with subdivisions into classes, subclasses, families, and subfamilies. For example, a number for a silicate might look like this: 76.1.2.1, where each number represents an increasingly specific division. Dana's system is relatively rigid, reflecting its antiquity, but it remains very precise for an organization based on chemistry and crystallography. It is still used in some academic or historical contexts, especially in the United States, because of its pioneering role in mineralogical classification.

Strunz classification : Developed by German mineralogist Karl Hugo Strunz in 1941, this classification also follows a chemical organization, but its system is more flexible and takes more specific account of crystal structure. Minerals are grouped into nine major classes, ranging from native elements to silicates, and each class is divided into subclasses based on particularities of crystal structure. The Strunz classification uses a three-part code for each mineral, reflecting the class, subclass, and position within the subclass. For example, quartz is classified under the code 4.DA.05, where "4" corresponds to the silicate class, "DA" to the tectosilicate subclass, and "05" is the identifier for quartz within that subclass. This system is regularly updated to incorporate new mineral discoveries, and is particularly useful for minerals with complex structures.