Abstract: An iron oxide based pigment in alpha-Fe.sub.2 O.sub.3 form, which contains the water insoluble part obtained by calcination of basic iron sulfate and/or jarosite based residues, this pigment being prepared by a process comprising calcining at a temperature from 600.degree. to 800.degree. C and during a period from 2 to 240 minutes basic iron sulfate and/or jarosite based residues, so as to decompose in an incomplete manner such basic iron sulfates and/or jarosite and to obtain in the calcined product an iron bonded sulfur content of more than 0.6%, and solubilizing the not decomposed iron sulfates with other soluble sulfated metals, such as zinc sulfate, by lixiviating the calcined product, these water-soluble compounds being then separated by appropriate processes.