Dana classification system

The classification of minerals was based on chemical composition by Dana in the fourth edition (1854, in two volumes) of his book System of Mineralogy. For the 20th century, this classification was completed thanks to scientific progress, particularly in the field of crystallography. In 1941, Karl Hugo Strunz used it to construct his classification. Dana's original classification was further developed, and a new classification was published in 1997. ==Classification structure==

Minerals are arranged in a hierarchical system. Each mineral has a classification number, made up of four numbers separated by dots, enabling unambiguous identification even when minerals are known by several names (synonymy). The first number represents the mineral class. The second number represents the mineral type, in some cases taking into account its atomic structure. The third number represents a group of minerals of similar structure. The fourth number gives the unambiguous identification of the mineral. ==Example==

Kieserite group. • 29. Acidic and normal hydrated sulfates • 29.06.: acid and normal hydrated sulfates of the formula AXO4-x(H2O) • 29.06.02.: kieserite group (monohydrates) • 29.06.02.01.: kieserite MgSO4-(H2O), space group C2/c • 29.06.02.02.: szomolnokite FeSO4-(H2O), space group A2/a • 29.06.02.03.: szmikite MnSO4-(H2O), space group A2/a • 29.06.02.04.: povinite (Cu,Fe,Zn)SO4-(H2O), space group P1 • 29.06.02.05.: gunningite (Zn,Mn)SO4-(H2O), space group A2/a • 29.06.02.06.: dwornikite (Ni,Fe)SO4-(H2O), space group C2/c • 29.06.02.07.: cobaltkieserite CoSO4-H2O, space group C2/c == Mineral classes ==