This paper deals with a crystal-chemical, infrared spectroscopic study of monoclinic epidotes from Praborna (St. Marcel, Val d'Aosta, Italy). The studied samples range in composition from clinozoisite (Czo) to Sr-rich piemontite (Pm). In the OH-stretching region, (Al,Fe3+)-clinozoisites show a single broad band centred in the range 3345-3380 cm-1 which is assigned to the [M2]Al-O10→H...O4-[M1,3](Al,Fe3+) configuration. The spectra of Sr-rich piemontites show a well-resolvable doublet at almost constant wavenumbers (3417/3454 cm-1) which can be explained by two simultaneous effects: (i) the entry of Mn3+ in the non-OH-coordinated M3 octahedra and, (ii) the entry of Sr substituting for Ca in A2.
|Number of pages||11|
|Journal||European Journal of Mineralogy|
|Publication status||Published - Jul 1996|
- Infrared spectroscopy
- St. Marcel