It was never mentioned.
It is called the Mirror of Erised. The mirror appears in Harry Potter and the Philosopher's Stone. Dumbledore hid the stone inside the mirror.
The Mirror of Erised does not show your face, it shows your hearts deepest desire. Since details of the mirror's design are unknown, it cannot be stated exactly what type of mirror it is considered to be. See related links for more information on types of mirrors.
Harry sees his family for the first time in his life through the Mirror of Erised. They're not really there. They're in the mirror. This is in the first book I think, "The Sorcerer's Stone". The Mirror of Erised is in Hogwarts in a deserted classroom.
Herself going to Hogwarts, herself being a witch, and not her sister.
It is unknown if Severus Snape has ever seen that mirror or what he saw inside it but it is likely that it had something to do with him and Lily being together.
The Mirror of Erised (desire spelled backwards) was a magic mirror that showed the looker their heart's deepest desire. Some lookers had trouble remembering that what they were viewing was not real, and were said to have wasted away from in front of the mirror. Dumbledore also used the mirror to help hide the Philosopher's (Sorcerer's) stone.
No. Albus Dumbledore sees himself reunited with his family, including his imprisoned father and deceased mother and sister.
The first time Harry Potter looked into the Mirror of Erised, he saw himself surrounded by his deceased parents, James and Lily Potter. They appeared proud and happy, and Harry felt a deep sense of love and belonging, something he had longed for since their death. The mirror showed him his deepest desire: a family and connection with his parents. This moment marked a poignant realization for Harry of what he truly wanted in life.
The Mirror of Erised, which is desire spelled backwards, shows your heart's greatest desire. Dumbledore explains that the happiest man in the world would see his own reflection. Whereas, Harry Potter who wanted a family that loved and cared for him, saw his entire family (minus the Dursleys).
The Mirror of Erised shows your hearts deepest desire. Albus Dumbledore placed the Philosopher's Stone inside the mirror and cast a powerful spell that meant only somebody who wanted the stone but who didn't want to use it, could get it.
In the mirror of Erised which, according to Dumbeldore shows " us nothing more or less than the deepest, most desperate desire of our hearts. You, who have never known your family, see them standing around you.".
In an interview Jk said that she would see everyone of her friends all save and Voldemort deafetead and she would be in a romantic embrace with "someone"