Spectrally-Resolved luminescence on hydrothermal aragonite

Chemical analyses performed on hydrothermal in aragonite from the Urals have shown an important amount of trace elements as well as REE as impurities. CL and TL spectra display similar features in which only small variations in the wavelength position are observed. Most of the glow peaks are associated to point defects due to impurities such as REE and Mn(2+) ion transitions in Ca(2+) positions. Nevertheless, the high intensity UV-blue emission seems to respond to a different pattern. The presence of Si as silicate anions along determined growth directions together with water between aragonite fibers can generate reactive bonded hydroxyl groups and non-bridging oxygen as probable responsible defects linked to the UV-blue emission.