The moon had the highest concentration of Taranium in the universe. The Time Lords mined it for their temporal technology, such as the Time Scoop. Ancient Gallifreyans worshipped it as a virgin goddess. (PROSE: Cat's Cradle: Time's Crucible) Pazithi Gallifreya was caught in one of Gallifrey's atmospheric flares and destroyed as the Eighth Doctor destroyed Gallifrey at the end of the War. (PROSE: The Gallifrey Chronicles)