Characterization of Portuguese gypsums as raw materials for Dermocosmetics

Portuguese gypsum deposits utilized by the cement industry were characterized mineralogically, chemically and technologically for possible application in dermocosmetics. The deposits studied (Loule, Obidos and Soure) correspond to small outcrops in diapiric anticline areas. In principle, they represent gypsites which are white, and generally of higher quality for traditional applications (e.g. white cement), or greyish, and generally not adequate for cements and mortars. The analytical methods used to characterize the materials were wet sieving and X-ray sedimentation, X-ray diffraction, X-ray fluorescence spectrometry and assessment of abrasiveness, plasticity, texturometrics (adhesivity and firmness), oil absorption and cooling rate. The Obidos gypsum displayed greater mineralogical and chemical quality (almost pure calcium sulfate) and had a finer grain size (<63 μm), whereas Loule and Soure gypsums contain mineralogical impurities (mainly quartz). The Obidos gypsum shows good characteristics in general for application in dermocosmetics because of its absorption, plasticity, adhesivity, firmness and low abrasiveness.