Invalid (Ore)

"An ore that was never meant to be obtainable (lol...)"

Invalid Ore was an Ore in Tangy Mines which was very hard to get.

Invalid could spawn everywhere, but you were more likely to find it in the Underworld.

Selling it did not give money, as it was not meant to be mineable, said by the game creator, MrCheezyPig (Saismee). It was removed in Beta 1.7.0.