Abstract <p>Determination of the fluorine content of natural samples is of interest from the geochemical and ecological prospects. Direct methods for the determination of fluorine, such as atomic emission spectrometry, are more preferable for the routine analysis of powder samples than methods including chemical sample preparation. The previously proposed method for determining fluorine by the first edge of the CaF molecular band (529.1 nm) with unidimensional calibration by certified reference materials adequate to the test samples in the composition and genesis for the reduction of matrix and spectral effects on the analyte was improved using n-dimensional calibration. To obtain reliable results in the range from 0.0040 to 65 wt % fluorine using spectral equipment with photoelectric spectrum recording and medium resolution, and substance introduction into an arc discharge by the spillage–injection method, we studied versions of multidimensional calibration by certified reference materials of varied compositions. The MLR calibration, constructed using certified reference materials of various compositions and macro- and microelement profiles, was found to be robust to variations in the chemical and mineral composition of powder samples. New data on the fluorine content of certified reference materials of the composition of rock and ash are presented.</p>