# Nickel–Strunz classification

Nickel–Strunz classification is a scheme for categorizing minerals based upon their chemical composition, introduced by German mineralogist Karl Hugo Strunz (24 February 1910 – 19 April 2006) in his Mineralogische Tabellen (1941). The 4th and the 5th edition was also edited by Christel Tennyson (1966). It was followed by A.S. Povarennykh with a modified classification (1966 in Russian, 1972 in English).
As curator of the Mineralogical Museum of Friedrich-Wilhelms-Universität (now known as the Humboldt University of Berlin), Strunz had been tasked with sorting the museum's geological collection according to crystal-chemical properties. His book Mineralogical Tables, has been through a number of modifications; the most recent edition, published in 2001, is the ninth (Mineralogical Tables by Hugo Strunz and Ernest H. Nickel (31 August 1925 – 18 July 2009)). The IMA/CNMNC supports the Nickel–Strunz database.

## Nickel–Strunz code scheme

The Nickel–Strunz code scheme is NN.XY.##x, where:
* NN: Nickel–Strunz mineral class number
* X: Nickel–Strunz mineral division letter
* Y: Nickel–Strunz mineral family letter
* ##x: Nickel–Strunz mineral/group number; x an add-on letter

## Nickel–Strunz mineral classes

The current scheme divides minerals into ten classes, which are further divided into divisions, families and groups according to chemical composition and crystal structure.
* elements
* sulfides and sulfosalts
* halides
* oxides, hydroxides and arsenites
* carbonates and nitrates
* borates
* sulfates, chromates, molybdates and tungstates
* phosphates, arsenates and vanadates
* silicates
* organic compounds

## IMA/CNMNC mineral classes

IMA/CNMNC proposes a new hierarchical scheme (Mills et al. 2009), using the Nickel–Strunz classes (10 ed) this gives:
* Classification of minerals (non silicates)
** Nickel–Strunz class 01: Native Elements
*** Class: native elements
** Nickel–Strunz class 02: Sulfides and Sulfosalts
*** Class 02.A – 02.G: sulfides, selenides, tellurides (including arsenides, antimonides, bismuthinides)
*** Class 02.H – 02.M: sulfosalts (including sulfarsenites, sulfantimonites, sulfobismuthites, etc.)
** Nickel–Strunz class 03: Halogenides
*** Class: halides
** Nickel–Strunz class 04: Oxides
*** Class: oxides
*** Class: hydroxides
*** Class: arsenites (including antimonites, bismuthites, sulfites, selenites and tellurites)
** Nickel–Strunz class 05: Carbonates and Nitrates
*** Class: carbonates
*** Class: nitrates
** Nickel–Strunz class 06: Borates
*** Class: borates
**** Subclass: nesoborates
**** Subclass: soroborates
**** Subclass: cycloborates
**** Subclass: inoborates
**** Subclass: phylloborates
**** Subclass: tectoborates
** Nickel–Strunz class 07: Sulfates, Selenates, Tellurates
*** Class: sulfates, selenates, tellurates
*** Class: chromates
*** Class: molybdate, wolframates and niobates
** Nickel–Strunz class 08: Phosphates, Arsenates, Vanadates
*** Class: phosphates
*** Class: arsenates and vanadates
** Nickel–Strunz class 10: Organic Compounds
*** Class: organic compounds
* Classification of minerals (silicates)
** Nickel–Strunz class 09: Silicates and Germanates
*** Class: silicates
**** Subclass: nesosilicates
**** Subclass: sorosilicates
**** Subclass: cyclosilicates
**** Subclass: inosilicates
**** Subclass: phyllosilicates
**** Subclass: tectosilicates without zeolitic H$_2$O
**** Subclass: tectosilicates with zeolitic H$_2$O; zeolite family
**** Subclass: unclassified silicates
**** Subclass: germanates