Abstract
The use of fire technology for transforming yellow goethite into red hematite was common, intentional and consolidated practice in Prehistoric settlements. Mineralogical structural analyses using X-ray powder diffraction (XRPD) and transmission electron microscopy (TEM) have been successfully employed for studying artificial hematite and for the estimation of the relevant transformation temperatures.Thermal treatments, over a temperature range of 250 up to 1000 °C, have been carried out on natural goethite (associated with quartz) collected from the palaeokarst caves at Ponte di Veja in North-Eastern Italy (Western sector of the Lessini Mountains) with the scope to compare the effects of heat treatment on natural goethite with synthetic goethite. This site provided extensively Fe-rich raw materials to the Upper Palaeolithic site Tagliente rockshelter.The mineralogical analysis demonstrated that selective broadening of some diffraction peaks occurs during the transformation for temperatures between 250 and 800 °C, confirmed by TEM analyses, in accordance with experiments executed on synthetic goethite samples.
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