It's been a question on royal ... Diana originally chose the Garrard ring because it reminded her of her mother's engagement ...

Walsh pointed out that due its ties to Diana, Kate's ring is the priciest ... unique and a departure from the blue sapphires seen across other royal rings with the soft pink hue of the centre ...

While at the Cheltenham Festival this month, it was fairly easy to catch a proper glimpse of Princess Eugenie's royal ring.

Royal fans have noted how ... the late Princess Diana, received from then-Prince Charles - a 12-carat, oval Ceylon blue sapphire, surrounded by a halo of 14 diamonds, and set in 18k white gold.

Royal fans will know that Prince William proposed to Kate Middleton with Princess Diana's iconic sapphire ... actress with a three-carat, oval-cut blue sapphire in a white diamond halo and gold ...

The royal is rarely seen without her iconic sapphire and diamond engagement band, which once belonged to Princess Diana Erin Hill ... surrounding a 12-carat oval blue Ceylon sapphire set in ...

While sapphire engagement rings are a popular choice with royals, with Prince William giving Princess Kate his mother's, Princess Diana's blue ... popularity of blue royal engagement rings ...