Banalinga

Banalinga, a stone found in nature, in the bed of the Narmada river in Madhya Pradesh state, India, is an iconic symbol of worship, based on either the scriptures or cultural traditions among the Hindus, particularly of the Shaivas and Smarta Brahmins. It is a smooth ellipsoid stone that represents a lingam, an anionic form of the deity Shiva.

The banalinga is also called the Svayambhu (self-born) linga as it is natural rather than artificial.

The forms of this lingam can vary in detail, from a simple roller shape roughly cylindrical banalinga to the stone carved with a thousand facets (sahasralinga) or of light relief in several human figures (mukhalinga).

Banalinga stones are quite strong and the hardness is a 7 on the Mohs scale.