Sapphire engagement rings are a popular choice among the royal family – not only does Kate Middleton famously wear Princess Diana's rock, but Princess Alexandra also owns a gorgeous blue ring.
MORE: Princess Anne received two almost identical engagement rings - but why?
The Queen's cousin announced her engagement to Sir Angus Ogilvy on 19 November 1962, and she was pictured wearing an oval sapphire flanked by two diamonds - however, it appears to have since been changed to a chunky gold band without the diamonds.
Not just any blue stone, Alexandra's ring boasts a giant cabochon sapphire, which is considered one of the oldest gemstone cuts and gives the finish of a smooth, rounded dome that highlights the blue colour.
WATCH: Which royal has the most expensive engagement ring? We reveal all
Princess Anne's engagement ring from Sir Timothy Laurence also has a large oval sapphire jewel in a cabochon setting in the centre and is flanked by a trio of sparkling gems on either side.
RELATED: Princess Alexandra's four-acre mansion where she lost the Queen's wedding present
READ: The Queen's cousin Flora Ogilvy's two weddings were filled with royal nods
While the design is eye-catching, the size is more modest and so it is not ostentatious or overbearing in any way. The Princess Royal wears her precious ring alongside her simplistic gold wedding band, which is believed to be made from Welsh gold as are most royal wedding rings.
The royal's engagement ring, pictured in 1962
Interestingly, the Queen's only daughter actually acted as Alexandra's bridesmaid in 1963! The royal married her husband Sir Angus Ogilvy in a breathtaking ceremony at Westminster Abbey in front of royals such as the Queen, Prince Philip, Prince Charles and Princess Margaret.
Princess Anne also has a cabochon sapphire engagement ring
Photos show a young Princess Anne looking beautiful in her simple bridesmaid's dress which featured cropped sleeves and a bow at the waist, paired with a white headpiece that wrapped around her elegant bun.
Meanwhile, Princess Alexandra was a stunning bride in a dress designed by John Cavanagh which featured a high neck and pretty lace, shipped over from France.
Princess Alexandra with bridesmaid Princess Anne on her wedding day
In one photograph of Anne and Alexandra, the pair were admiring a gold bangle given to the bride as a present. Unfortunately, some of her wedding presents were later stolen from her home Thatched House Lodge in Richmond Park, which she shared with her husband Angus and her two children James and Marina.
SEE: 21 royal engagement rings that are total show-stoppers: From Zara Tindall to Countess Sophie
Planning your wedding? Sign up to HELLO!’s brand new Bride Guide newsletter for expert advice, budget help, wedding inspiration and real life stories delivered straight to your inbox.