Mrs. Weasley walks up to the box and takes out several pieces of broken glass. She takes them back to her desk and takes out her wand. Pointing her wand at the pieces of glass, she says, glas reparo. The glass shakes a little, but it does not repair itself. Not knowing what went wrong, Mrs. Weasley just stares at the glass. She, then, points her wand at the shards of glass and says goblet reparo. The glass transforms into a crystal goblet. You must have to know what the glass was originally to be able to repair it, she thinks to herself.