KNa₄Ca₄Si₈O₁₈(CO₃)₄(OH,F).H₂O

This sample of carletonite is displayed in the Smithsonian Museum of Natural History. Carletonite is a mineral that contains fluorine with the composition KNa₄Ca₄Si₈O₁₈(CO₃)₄(OH,F).H₂O. The sample at left is about 6 cm across and is from Mon Saint-Hilaire, Quebec, Canada.