Mirror of Darkness

The Mirror of Darkness is a object that appears in Ultima IX in the Guardian's fortress, and is roughly three meters high. It appeared to be a spying instrument of the Guardian, as it enabled him to see far away places (but not everywhere, as Stonegate was protected from its view). The mirror later showed the Avatar the destruction of the city Skara Brae at the Guardian's orders. It was destroyed in the end, when the Avatar casted Armageddon.

Confusion arises because a similar mirror can be found in Lord British's sleeping room. It only shows Armageddon when used, then breaks.

Trivia

 * In the original plot, both mirrors had more of a role, as the Guardian used his mirror to send Lord British horrible visions through the other mirror. Thus why the player gets points when breaking it.
 * Using the mirror in-game shows the Armageddon video.