
Nickel–Strunz classification is a scheme for categorizing minerals based upon their chemical composition, introduced by German mineralogist Karl Hugo Strunz in his Mineralogische Tabellen (1941). The 4th and the 5th edition were 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, having been revised by Ernest Henry Nickel. The IMA/CNMNC supports the Nickel–Strunz database.
The Nickel–Strunz code scheme is NN.XY.##x, where:
The current scheme divides minerals into ten classes, which are further divided into divisions, families and groups according to chemical composition and crystal structure.
IMA/CNMNC proposes a new hierarchical scheme (Mills et al. 2009), using the Nickel–Strunz classes (10 ed) this gives: