Eye of Akasha

Eyes of Akasha were small, red, spherical objects the size of cricket balls. They would give off light and tertiary radiation.

In one of his earlier regenerations, the Doctor kept a broken Eye of Akasha in his house on Allen Road. At some point after the 1980s, a squadron of Judoon came to get the Eye. He was able to swap it with a cricket ball and let the Judoon leave with it. (IDW: The Forgotten)