A royal headpiece is a type of crown or hat worn by royalty. The three most common types are the CORONET, TIARA, and DIADEM. A CORONET is a small crown with a circular band and often has jewels or other decorations. A TIARA is a type of crown that is usually made of metal and has a high peak in the center. A DIADEM is a type of crown that is usually made of precious metals and has a band of jewels around the head. All three of these royal headpieces are symbols of power and authority.