The Characteristics and Possibility of using Al-Lisi (Yemen) Pumice Rocks as Abrasives and Polishing Material in Dental Laboratories Instead of Imported Pumice
The pumice rocks crop out at Al-Lisi locality, which lie at about 15 km east of Thamarcity. Pumice rocks occur within acidic volcanic rocks sequence consisting of rhyolite, obsidian and pyroclastic rocks. Volumetric study of Al-Lisi pumice rocks shows similarity with the imported pumice.Petrographic examination shows that the pumice rocks of Al-Lisiare composed mainly of more than 75% silica groundmass with embedded phenocrysts of quartz, sanidine, plagioclase, anorthoclase and pyroxene. Chemical analysis shows that…