Unsurprisingly, most couples opt to buy an antique ring or an antique style diamond ring in order to stand out from the rest of the crowd on their special day.       When it comes to the style of the old eras, one of the most popular options is sapphire and diamond rings. In fact, most of the royalties also loved to flaunt antique sapphire and diamond engagement rings. In fact, the popular engagement ring of Princess Diana displayed a beautiful diamond and sapphire combination. This engagement ring is counted amongst one of the most popular diamond rings in history. The Princess Diana diamond engagement ring has a huge 12-carat sapphire stone of Vivid Blue color is set at the center of a white gold band. In addition, the center diamond is highlighted by giving a halo of tiny diamond solitaire around it. Currently, this amazing diamond engagement ring is owned by the Duchess of Cambridge, Kate Middleton. Prince William proposed to her with his late mother’s diamond engagement ring in order to make his mother an important part of their relationship.