Syamantaka Jewel

A jewel that gives magical powers. It was owned by Satrajit, Satyabhama’s father, who received it from Surya. Everyone wanted it, even Krishna, but he never got it. In the end it was owned by Akrura in Dwaraka. What happened to the jewel after Dwaraka was destroyed is not known.

http://hindumythologyforgennext.blogspot.com/2012/07/krishna-and-satrajit-part-1-of-2.html