EPR Spectroscopy of the Ground Electron State of the Fe²⁺ Impurity Ion in Amethyst

Properties of two lowest electron levels of the Fe²⁺ impurity ion in a natural amethyst are studied by continuous wave electron paramagnetic resonance spectroscopy in the Q-band. It is established that the these levels present quasi-doublet \(\left| { \pm 2} \right\rangle\) $\left|\pm 2\right.〉$ with zero-field splitting of 30.9 ± 0.2 GHz. Orientation of principal magnetic axes and value of g-factor of this paramagnetic center are determined.