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…

Chemical, Physical and Geotechnical Properties Comparison between Scoria and Pumice Deposits in Dhamar – Rada Volcanic Field -SW Yemen

A study of the chemical and physical properties of Scoria and Pumice deposits in Dhamar – Rada volcanic field, and assess these deposits in manufacturing lightweight concert. The study area is located 95 Km SE Sana’a city (the capital of Yemen), extends to southeast of Dhamar city and spread to Rada` district. It is covering an area of approximately 2500km2. Thirty representative samples were collected from different areas of Dhamar – Rada volcanic field, as 15 samples for Scoria and 15samples for Pumice deposits…