Neumann lines of a piece of the Sikhote-Alin meteorite.
Neumann lines are found in some iron meteorites. They are groups of very fine parallel lines that cross each other at various angles. Irons containing Neumann lines can easily be cleaved in three mutually perpendicular directions. They are named after their discoverer, the German crystallographer and mathematical physicist Franz Ernst Neumann (1798–1895) who first studied them in 1848.