Chloritoid inclusions in pyrite from Navajún, Spain

Almost pure Fe end-member chloritoid was identified as the major included phase in large cubes of pyrite from Navajún, Logroño, Spain. The silicates in the pyrite matrix as well as isolated mineral separates were analyzed by electron microprobe, X-ray diffraction, and Mössbauer spectroscopy. Mössbauer spectra taken at room temperature and at 77 Kelvin show a superposition of an Fe²⁺ doublet and at least one Fe³⁺ doublet. The chloritoid from one of the pyrite cubes analyzed is more oxidized than that in the two other cubes. Mössbauer data give some evidence that this may be due to the presence of Fe³⁺ in sites normally occupied by Fe²⁺. In all samples, significant effects due to preferred orientation have been observed in both the X-ray and Mössbauer spectra.