All materials, including minerals, possess the property of becoming magnetized in the presence of an applied magnetic field. This property is called magnetic susceptibility.
Different materials have characteristic susceptibility values. Susceptibility is important in interpretation of magnetic data in modelling and in verification of different lithological units. The content of magnetite can also be evaluated from magnetic susceptibility.
In basic measurements, magnetic susceptibility can be measured both on hand samples and on drill core samples. The sample must fit into tube with length of 10 cm and diameter 9.5 cm. For samples that require more sensitive measurements with specialist equipment, the maximum diameter is 5 cm and the maximum length is 7 cm. Mass susceptibility can also be measured on powdered samples with minimum weight 100 g.