Unlike paleomagnetism, which measures the sample's polarity relative to the earth's magnetic poles, mineral magnetism samples do not need to be measured in situ, or have their original orientation noted. Magnetism measurements are relatively fast, inexpensive and easy to make. Perhaps the greatest advantage of this analysis, however, is that it's non-destructive, which means the sample can be used for another analysis. Any non-destructive method is a great asset. When samples are taken from cores , the mud is dried, then packed into small, 1x1x1 cm cubes and weighed.
Magnetic susceptibility measures the ability for samples to become magnetic.
We apply a small magnetic field to each sample and measure susceptibility again. Finally, we apply a strong magnetic field along one axis and measure susceptibility, then reduce the strength of the field and reverse it, measuring susceptibility one last time.