Fractoluminescence spectra in crystalline quartz

Fractoluminescence and charge emission upon three-point-bending fracture of synthetic and natural quartz crystals have been studied. Broad luminescence bands centered at about 2.0, 2.9, and 5.0 eV have been observed in both cases. Time-resolved luminescence measurement could be performed on the 2.0 and 2.9 eV bands. The 2.9 eV band has a maximum intensity at about 5 ms after the fracture, and this band decayed within about 13 ms. On the other hand, the decay profile of the 2.0 eV band differed between synthetic and natural crystals. The 2.9 eV band might be due to the relaxation of the oxygen vacancy on the fracture surface, as in the case of silica glass. The 2.0 eV band seems to be due to an impurity center.