New molecular data on exotic phases mineral occurring in fumarolic systems are reported in this paper. Fumaroles, vents that emit hot gases and vapor, are accompanying phenomena of volcanic activity. Such phenomena are also observed within the framework of self-ignited burning coal seams and coal heap. Rare anhydrous sulfates (millosevichite, mikasaite, efremovite, godovikovite, sabieite, and steklite) are signature minerals of such encrustations. Six synthetic anhydrous sulfates were prepared from the hydrated analogues, and were investigated using both a bench-top Raman microspectrometer and a portable Raman spectrometer. This comparative approach can help further steps for the successful deployments of miniature Raman tools in situ under field conditions. New measurements show that the performance of a light-weight portable Raman spectrometer with near infrared excitation was sufficient for the unambiguous discrimination of the investigated sulfates.
Košek F., Culka A., Jehlička J. (2018): Raman spectroscopic study of six synthetic anhydrous sulfates relevant to the mineralogy of fumaroles. Journal of Raman Spectroscopy 49, 1205-1216. (DOI)