“Princess Diana’s ring features a 12 carat oval blue sapphire, surrounded by 14 diamonds and has since become almost as famous as its original owner.
“Princess Diana’s ring choice was unexpected at the time because it was purchased directly from a catalogue, as opposed to being a custom-made design.
“Following Prince Charles’ proposal, Princess Diana was reportedly presented with a selection of engagement rings before choosing her favourite, a ring that resembled one her mother owned.
‘This poignant moment was covered in the fourth season of The Crown; Diana, portrayed by Emma Corrin, selects a ring that reminds her of her mother’s, before describing the sapphire stone as ‘the same colour as my eyes’.
source: express.co.uk