The use of magnetic properties for the age assessment of archaeological and geologic materials. It uses the natural remanent magnetization acquired at a specific time. Its direction can be compared with timescales of geomagnetic secular variations, polarity reversal sequences, or polar wander paths. Its intensity can be converted to the strength of the field in which it was acquired and so compared with the timescales of intensity changes of the geomagnetic field. Viscous remanent magnetization may sometimes be used to establish how long the sample has been in a specific position.