(Na,Ca)₈(Si₆Al₆)O₂₄(CO₃)₂

This sample of cancrinite is displayed in the Smithsonian Museum of Natural History. Cancrinite is a silicate mineral with sodium, calcium and aluminum with the composition (Na,Ca)₈(Si₆Al₆)O₂₄(CO₃)₂. The sample at left is about 8 cm across and is from Litchfield Township, Maine.