Paramagnetic Resonance and Optical Spectrum of Iron in Beryl

The paramagnetic resonance spectrum of Fe³⁺ in beryl was measured at 20^∘{} and 290^∘{}K. In addition to this spectrum many weak lines were observed and possible explanations of these lines are discussed.The optical spectrum shows a spectrum characteristic of trivalent iron. In the infrared region there are several groups of sharp lines whose origin is not yet known.