This device is called a gas discharge tube. It is used to protect from overvoltages, e.g. when a lightning strikes nearby (it won't protect neither you nor the TV from a direct hit). No burn marks means that this device has seen no or only negligible overvoltages, which is not unusual.
You probably found this at the antenna input of the TV as this is likely the point of entry for overvoltages picked up by the antenna circuit.