Neumann's principles

Neumann's principles state that the physical properties of a crystal are related to its symmetry. Essentially, if a crystal has certain symmetrical features, its behavior—such as how it conducts heat, conducts electricity, or responds to stress—must also reflect those symmetries. These principles help scientists predict how materials will behave based on their internal structure, ensuring the properties are consistent with the crystal's symmetry. This understanding is fundamental in materials science for designing and analyzing materials with desired characteristics.