Ktarian antique was a valuable collectible because of its age and condition from the Ktarian civilization.

In 2369, when the USS Enterprise-D visited the station Deep Space 9, the ship's chief engineer, Geordi La Forge, wanted to take a look at the Ktarian antiques on the station. He understood that one of the antiques was a 21st century plasma coil in almost perfect condition. (TNG: "Birthright, Part I")