Structural point defects in "Iceland spar" calcite

Trace element concentrations by micro-PIXE, cathodoluminescence (CL) emissi on spectra and electron spin resonance (ESR) spectra of Mn2+ in "Iceland sp ar" calcite have been measured. The average rare earth elements (REE) abund ances of the Iceland spar calcite revealed a concave shape with positive Eu and Tb anomalies. All samples show comparable average REE abundances compa red to average chondrites standard. The REE signal in hydrothermal solution seems to be similar for the different locations and age of formation altho ugh the absolute REE concentration in the solution was certainly different. The CL-properties of investigated Iceland spar varied from orange to green . The orange luminescence is based on Mn2+ in Ca-position of calcite while this uncommon green luminescence is most likely attributed to UO22+ complex ions associated with electron-hole centres. (C) 2001 Elsevier Science B.V. All rights reserved.