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 edited by Christel Tennyson too (1966). It was followed by A.S. Povarennykh with a modified classification (1966 in Russian, 1972 in English).