The Enchanted Mirror

The enchanted mirror possesses magical abilities, allowing its user to see anything he or she wishes to see, a power known as scrying. It was presumably given to the Beast by the Enchantress as his only window to the outside world. It's unknown if it has always been enchanted, or that it was an ordinary mirror owned by the prince and became enchanted along with the whole castle.The mirror was first used by the Beast to see Belle in her room, where he hears a conversation between Belle and the Wardrobe, and upon learning that Belle wanted nothing to do with him, he loses hope that she would see him as anything else but a monster. When Beast lets Belle use the magic mirror, she sees her father dying in the woods, and with only hours left before the rose wilts, the Beast allows her to leave. He gives her the mirror so she can still see him, and to remember him by. Shortly after, Belle uses the mirror to reveal the existence of the Beast to an angry mob of villagers, in order to prove that her father isn't insane. However, Gaston, who becomes infuriated upon learning that Belle would consider him a monster rather than the Beast, takes the mirror from her and uses the image of Beast to stir up the crowd. He takes the mirror all the way to Beast's castle. From there the mirror disappears. It could have been recovered by Mrs. Potts or one of the other castle staff while they attacked Gaston and the angry mob and it may still be in Prince Adam's possession, if it hasn't been taken back by the Enchantress, due to no longer being needed.