Planet (Where Diamonds Are Worthless)

The First Doctor, Ian Chesterton and Barbara Wright visited a planet. Ian noted that it looked "quite ordinary". The land contained grass as well as visible mountains. However, the land wasn't very stable, with some weak spots that would break into small holes previously unseen. Inside these holes there were diamonds, but the Doctor noted that they have no value because of the abundance of it on the planet. The diamonds also contained strange properties that would cause them to disappear if carried into the TARDIS. (COMIC: Where Diamonds Are Worthless)