Alcyone
From Tardis Wiki, the free Doctor Who reference
The Alcyone, the Breath of Hearts and Ashes as named by the Vigilant eremites of Andurax, was a gemstone. As of 1992, only four such stones remained in the universe.
The Harmony Shoal used its powers to fully conquer Nixtus III. After being accepted by the native species, the gemstone was used to shut down the decentralised nervous system of the Zanthians to establish a full symbiotic relationship, to effectively replace them. The gemstone also interfered with the Hazandra, disabling Grant's powers. It was finally retrieved by Jennifer Fletcher and Grant. (COMIC: Ghost Stories)
