Magnetic inclusions in diamonds

We demonstrate that the pyrrhotite that commonly occurs as inclusions in diamonds is capable of carrying strong and stable remanent magnetizations. This suggests that with suitable samples, it may be possible to use such inclusions to obtain information about the geomagnetic field, such as the paleointensity, during key intervals of geologic time. The pyrrhotite inclusions examined here exhibit a strong and pronounced anisotropy of magnetic remanence that is coupled to the crystal structure of the diamond. While this anisotropy of remanence may complicate efforts to obtain paleointensity data, we propose that it may provide a valuable way to uniquely identify individual diamonds that contain even minute inclusions of pyrrhotite.