Al₂[C₆(COO)₆].16H₂O

This sample of mellite is displayed in the Smithsonian Museum of Natural History. Mellite is an oxide mineral of aluminum and carbon with the composition Al₂[C₆(COO)₆].16H₂O. It contains the chemical form benzine hexacarboxylate. It is a rare secondary mineral in lignite deposits. The sample at left is about 7 cm wide and is from Csordakut coal mine, Tatabanya, Hungary.