Pumice (image) Georgia Institute of Technology Share Print E-Mail Caption Georgia Tech Assistant Professor Josef Dufek studied how pumice rocks travel through a volcano. The process affects the size of particles that are released during an eruption. The pictured rocks are from Mt. St. Helens in Washington. Credit Josef Dufek Usage Restrictions None Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.