But did you know that blue sapphires have an equally gorgeous, yet much more affordable sibling stone, the white sapphire? It combines the look of a diamond with the glamour, mystique, and rich history and meaning of a sapphire. Her daughter-in-law Kate Middleton re-ignited the trend when she received the same ring from Prince William in 2010. Blue sapphires have been a popular choice for engagement rings for decades, in part thanks to Princess Diana, who wore a 12-carat halo sapphire when she got engaged to Prince Charles. If you’re exploring alternatives to a diamond for your engagement ring, you’ve probably thought about sapphires.