Zeolite 'Sieve' (IMAGE) Rice University Caption Zeolites are a fine lattice, a molecular sieve that can let molecules of a certain size pass while blocking others. Credit Rice University 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.