a diamond 'tiara'
(..) For centuries. There's no person alive today who's seen it. Excuse me, can someone tell me what bloody diadem is? It's a sort of crown. You know, like a tiara. Harry! Hi, there. Six months she doesn't see me and it's like I'm a frankie first-year. I'm her brother! (..)2011 Harry Potter and the Deathly Hallows: Part 2