On the photoconductivity of amethyst quartz

Abstract

This paper describes an investigation of the photoconducting nature of amethyst quartz. Measurements of photocurreut were made for varying voltages, intensities, radiations and temperatures. A spectral sensitivity curve of photoconductivity duplicates the optical absorption in the visual region identified as the F-band. The photocurrent is found to be proportional to light intensity and voltage; in the latter case secondary currents deviate the relationship from strict linearity. Under constant irradiation of light in the maximum of the F-band, the crystal is shown to be "excited". Lastly, measurements of photocurrent At. Different temperatures under radiation sources that yield both the electron primary current and the positive primary current, show that the curves obtained are identical with those obtained by Pohl and collaborators in the case of coloured rocksalt. The similarity of the behaviour of amethyst quartz and coloured rock salt is so very striking that it seems very reasonable to ascribe the colouring of amethyst quartz to F-centres caused by high frequency radiations.