The objectives of this study are to explain the possible mode of origin and to record the occurrences of the alunite in the lower part of the Shale Member, South Jordan. Alunite was characterized by field work, SEM, XRD and XR Microanalyzer. The results of the field, chemical and mineralogical studies indicated that the alunite occurs as small fine-grained white spots along bedding planes within the lower part of the Shale Member, South Jordan. The sulfur trioxide (SO3) is related to the presence of gypsum and alunite. Iron sulfides (source of sulfur) could be originally produced by mineral replacement of chitinous tests of graptolites in oxygen deficient marine environment.