Smooth stones found on the bed of the Narmada River in central and western India, which are worshipped as the Hindu god Shiva, representing self-created (svayambhu) lingams. Ovoid or cylindrical, banalingams vary in size; many have light-coloured markings or striations said to represent feminine divine energy. They are usually set on brass or stone pedestals to be worshipped. Some scholars suggest that this practice originated in prehistoric cults’ worship of stones as representations of deities.