Kaustubha

It is believed in Hindu scriptures to be the most magnificent ratnam in all of creation, at the time of the churning of the ocean, and acts as a symbol of divine authority.

[2] In Hindu mythology, the devas and the asuras performed the churning of the ocean of milk (Samudra Manthana) in order to obtain amrita, the elixir of immortality.

Suras and Asuras of enhanced strength lustily roared again and began to churn the ocean keeping Cintāmaṇi in the middle.Krishna is described to be wearing the ruby in the Mahabharata:[5] Now before them they saw the color of the transcendental body of Lord Krishna, exactly like the hue of a newly arrived cloud in the sky.

He appeared before them nicely covered with yellow colored silken garments, with four hands like Vishnu, and carrying the different symbols of the club, the conchshell, the disc and the lotus flower.

His eyes appeared to be spread like the petals of a lotus flower, and His smiling face exhibited the symbol of eternal peace and prosperity.