Copper was a reddish brown color that resembles the metal copper.
The War Doctor wore a double-breasted waistcoat of copper moleskin with a shawl collar and a double fob chain of bronze when he helped Voord during the Last Great Time War. (COMIC: Four Doctors)
The steward of Platform One wore a copper-coloured robe. (TV: The End of the World)
Gallifrey had two large moons, one of which was the copper-coloured Pazithi Gallifreya. (PROSE: Cat's Cradle: Time's Crucible) Quinnis had a copper-coloured sky. (AUDIO: Quinnis)
The Lakhotha (PROSE: Scribbles in Chalk) and the Rhumons had copper-coloured skin. (PROSE: Twilight of the Gods) The Jaftee had copper-coloured hair. (PROSE: Shining Darkness)