Oxidation effects in beryl induced by synchrotron radiation

Successive fluorescence-yield X-ray absorption near-edge structure spectra, collected within 30 s in quick-scan mode, show the extremely fast oxidation process of iron in natural, yellow and green beryl induced by synchrotron radiation. Initially, the Fe3+/Fe2+ ratio equals 0.52, which, with increasing time of exposure to the incident X-ray beam, increases to 2.03. The oxidation process starts about 5 min after exposure to the X-ray beam. From that moment on, after 30 s, the amount of ferric iron increases by ∼1.3%, implying that the exact amount of ferrous and ferric iron in beryl cannot precisely be determined when using the much slower, step-by-step scanning mode.