Gmelinite is a silicate of the zeolite group which is subdivided into three minerals based on dominate presence of sodium, potassium or calcium. These samples have the indicated composition Na4(Al4Si8)O24.11H2O. The left sample is about 6x12 cm and is described as gmelinite with analcime. The right sample is just labeled gmelinite. The samples are from Pinnacle Rock, Five Islands, Nova Scotia, Canada. These samples are on display in the Smithsonian Museum of Natural History.