Emerald (colour)

Emerald was a shade of green named after a substance.

Ace wore an emerald t-shirt under a black cardigan. (TV: Battlefield)

Bill Potts wore an emerald velvet coat during a visit to the 1814 frost fair. (TV: Thin Ice)

The Master wore an emerald cravat when posing as 'the other Doctor'. (AUDIO: Dominion)