Celestine from Valea Sarii (Vrancea region): New Data and Crystal Structure Refinement

Abstract

In the paper has been analyzed the crystal structure of a celestine sample from Valea Sarii (Vrancea region, Romania) located in the Eastern Carpathians Foredeep. The celestine sample was also studied by optical microscopy, chemical and thermal analysis. The unit cell parameters of the celestine structure refined in the space group Pnma were: a=8.39769 �, b=5.38415 �, c=6.88167 �, Z=4. The chemical composition of the celestine crystals was determined by EDX analysis. The optical characteristics of the sample were studied by optical microscopy. A new set of the unit cell parameters and fractional coordinates of the celestine crystal structure were determined. Also were determined the bond lengths in the Sr-O12 and SO4 polyhedra. The sample was collected in the massive mineralization area of the Valea Sarii ore deposit, the largest celestine ore deposit in Romania.