Indus Valley Civilization copper anthropomorphic idols constitute a rare though fine example of abstract silhouettes of the human figures, which were created by the indigenous inhabitants of the Ganges river valley. Often discovered together with other implements such as harpoons and rings, such enigmatic figures were cast in molds from copper and then hammered, with the chisel marks left easily discernible. The natural attractive patina and the earthy deposits often remaining on them are signs of a prolonged permanence under the surface of the earth. It has been suggested that these idols functioned as protective guardian spirits.