Natural Volcanic Pumice (IMAGE) Australian National University Caption This is Dr. Charles Le Losq with natural volcanic pumice from the eruption of the supervolcano Toba in Indonesia that took place 74,000 years ago. Credit Stuart Hay, ANU Usage Restrictions None License Licensed content 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.