Camilla, Duchess of Cornwall – Estimated value £300K

According to the jewellery expert, Camilla’s diamond engagement ring from Prince Charles is worth a staggering six-figure sum, although it is not one of the most famous royal engagement rings.

Camilla’s engagement ring features a central emerald-cut diamond flanked by baguette diamonds.

Poignantly, the ring is thought to have belonged to Charles’ beloved grandmother, the late Queen Mother, making the ring a family heirloom.