Pazithi Gallifreya was one of two moons orbiting Gallifrey. Its coppery shine was visible even during the day. It was heavily industrialised by the Gallifreyans for smelting purposes.
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)
During the destruction of Romana III's Gallifrey by the Eighth Doctor during the War, Pazithi Gallifreya was caught in an atmospheric flare and destroyed. (PROSE: The Gallifrey Chronicles)