The natural mineral chrysocolla (CuSiO3·2H2O) has been investigated in terms of thermally stimulated luminescence and EPR measurements. The glow curves for natural samples present three glow peaks at 190, 357 and 450°C. Pre annealed and subsequently irradiated samples give rise to four glow peaks at 140°C, 193°C, 305°C and 450°C. The formation of Ho centers at the expense of water molecules present in the channels has been identified by EPR measurements.
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This work was supported by FAPESP and CNPq. One of us, P.C. Selvin gratefully acknowledges FAPESP for a fellowship. The help rendered by Mr. W.E.F. Ayta throughout the course of this study is gratefully acknowledged.