The water of crystallization in gypsum: comparing the laser excited Raman spectrum with that obtained by means of a mercury resonance radiation exciter (Rasetti technique)

Here we consider the gypsum mineral to investigate its broad scan Raman spectrum. The presence of water of crystallization is detected and its OH-stretching spectral region deconvoluted in q-Gaussian functions. That is, we follow the same approach that we used recently for minerals of the natrolite and vivianite groups. In the case of gypsum, we consider the Raman data from Rappal Sangameswaran Krishnan, 1945, and compare the bands given in his work with the components that we can obtain from the spectra provided by RRUFF database. We find a remarkable agreement between R. S. Krishnan’s data and the decompositions in q-Gaussian functions. We will describe also the experimental method used by Krishnan, based on the Franco Rasetti technique with mercury resonance radiation excitation. In the RRUFF database, we can also find an infrared spectrum; we considered it and decomposed in q-Gaussian and q-BWF functions.