kaustubha | कौस्तुभ

kaustubha mani (Devanagari: कौस्तुभ मणि ISO15919: kaustubha mani) is a divine jewel which has eternally been worn by Shri Krishna on his chest.

In the lila of churning of the milk ocean, 14 things emerged from the kshirasagara. Kautubh mani was one of those things. It was given to the Lord, who wore it on His chest.

Reference: Practise Powerful Meditation, Ch. 8