Abstract
In the present study, cathodoluminescence (CL) providing information about surface rather than bulk material reveals blue and red emissions within the sanidine feldspar from the Eifel Mountains, Germany. The emission line occurring in the blue region at about 450 nm reflects Al−O
−
−Al structural defects, although distribution maps of the major elements, including Si, Al, and K, do not display a clear correlation with the CL properties of the sanidine feldspar. Dominant emission being in the longer-visible wavelength region (red region) ∼730 nm is assumed to be caused by Fe
3+
activation attributed to Fe
3+
−Al
3+
substitution. Much less is known about the spectral characteristic of the feldspar CL emission, and the application of an older luminescence technique yields encouraging results for the practical application of the feldspar identification.