ABSTRACT
The mineral glauberite is one of many minerals formed in evaporite deposits. The mineral glauberite has been studied using a combination of scanning electron microscopy with energy dispersive X-ray analysis and infrared and Raman spectroscopy. Qualitative chemical analysis shows a homogeneous phase, composed by sulfur, calcium, and sodium. Glauberite is characterized by a very intense Raman band at 1002 cm−1 with Raman bands observed at 1107, 1141, 1156, and 1169 cm−1 attributed to the sulfate ν3 antisymmetric stretching vibration. Raman bands at 619, 636, 645, and 651 cm−1 are assigned to the ν4 sulfate bending modes. Raman bands at 454, 472, and 486 cm−1 are ascribed to the ν2 sulfate bending modes. The observation of multiple bands is attributed to the loss of symmetry of the sulfate anion. Raman spectroscopy is superior to infrared spectroscopy for the determination of glauberite.
ACKNOWLEDGMENTS
The infra-structure support of the Discipline of Nanotechnology and Molecular Science, Science and Engineering Faculty of the Queensland University of Technology, is gratefully acknowledged. The authors would like to acknowledge the Center of Microscopy at the Universidade Federal de Minas Gerais (http://www.microscopia.ufmg.br) for providing the equipment and technical support for experiments involving electron microscopy.