The Salagrama is a small stone, actually an ammonite, a fossil genus of marine cephalophod, and is considered by l3rahmins to be a natural representation of Vishnu. It plays an important role in the worship of a Brahmin, who is considered a living, earthly form of the deity. The salagrama is mentioned in the Atharva Veda where it is written that any Brahmin’s house that does not contain the salagraina is to be considered as impure as a cemetery.
Salagramas are to be found in the Gundak river in Nepal. They are black or dark coloured, round or oval in shape, striated, umbilicated and ornamented with natural tree like markings. The most sought after are the ones that are perforated in one or more places worms. The curves of the striations signify the various norms of Vishnu. A black Salagrama with a replica of the discus in it is capable of bestowing great happiness, health, wealth and children. A half green Salagrama will drive away all sins and one which has the shape of the umbrella on it will make the possessor a monarch. The worship of Salagrama does not call for elaborate prayer ceremonies. Its very presence assures happiness.
The reason for its sacredness is that once Shani called on Vishnu, who had transformed himself into a mountain. This angered Shani who became a worm (Vajrakita) and afflicted him for twelve years. At the expiration of the time Vishnu regained his original shape and ordered that henceforth the stones of this mountain will be worshipped as a representation of himself.
The salagrama is kept in the home, wrapped in a cloth, frequently lathed and perfumed and sometimes having water dripping on it. Though the stone is Vishnu in its visual form, it is also a lingam, the Shiva phallus, and a type of the Cosmic Egg.