But the talk of the town wasn't just about how lovely the ring is (although, of course, it was), but also the striking resemblance it held to Princess Eugenie's mother, Sarah, Duchess of York's, engagement ring.
The Duchess' ring was given to her in 1986 by Prince Andrew, the Queen's second son, and featured an oval-cut Burmese ruby set within a halo of 10 pointed diamonds.
Legend has it that Prince Andrew had already purchased an emerald to give to Ms Ferguson, but she was insistent on receiving a ruby ("to match her hair"), and the ring was then designed by both the Prince and the bride-to-be with royal jeweller Garrard.
Both Sarah, Duchess of York, and Princess Eugenie's coloured-stone-and-diamond-halo choices are following in a long-standing royal tradition. Looking over the assortment rings received by royal brides throughout the years reveals that that particular style is immensely popular.
The start of the trend could potentially be traced back to the enormous Colombian emerald Wallis Simpson received from the abdicated King Edward VIII. The 20-carat stone was bordered by a ring of white diamonds and was made by Cartier. The yellow-gold ring was engraved with the words, "We are ours now 27.X.36"—their initials and the date of their engagement.
That ring style was echoed in Lady Diana Spencer's choice. Newly-engaged to the Prince of Wales in 1981, Lady Diana chose the 12-carat Ceylon sapphire ring from a Garrard catalogue. It was valued at around 28,000 pounds sterling at the time (around $95,000 AUD in 2018).
According to the Daily Mail Lady Diana told jewellery historian Leslie Field she wasn't bothered about the size of it.
"She [Diana] had obviously already said she would like a sapphire; she had half a dozen rings [to select from] and she chose this one purely because she liked it."
"Somebody came up with the story that she immediately went for the biggest, but I asked her and she told me it definitely wasn't the biggest, she simply thought it was very beautiful."
Famously, the ring was then passed to Kate Middleton from Prince William, after which it was then cheekily referred to as the 'Commoner's Sapphire,' as both Diana and Kate came from outside the royal family.
And gemstones are certainly not out of place in the royal jewel vault. Royal engagement rings are almost overwhelmingly gemstone-based. Only a few of the rings in the family—namely Queen Elizabeth's, Duchess Camilla's and Meghan Markle's—are diamond-focused, whilst the others favour sapphires as the stone of choice.
The element of sentimentality that comes with Eugenie's choice is fairly apparent—her selection of both a coloured gemstone over a diamond, and the specific diamond-halo design effectively mirrors a long line of royal rings before her. And this tradition of keeping things within the family is something the royals specialise in.
Throughout their long, diamond-studded history the royals have been prone to reuse or repurpose jewellery for engagement rings rather than buy something new. Queen Elizabeth's ring was made using diamonds from Prince Philip's mother's tiara; whilst Duchess Camilla received a ring that belonged to the Queen Mother, a piece that was reportedly given to her to celebrate the birth of Princess Elizabeth, later Elizabeth II.
Similarly, both Kate Middleton and Meghan Markle received rings with nods to their late mother-in-law, Diana, Princess of Wales. Kate received her engagement ring, whilst Meghan's is made of diamonds taken from her personal collection.
We think it's safe to stay we can expect a lot more gemstones with diamond halos from royal brides in the years to come.