Amazing dear Beth, many congratulations on your yet another great find. Its a real gem knowledge for me and I do think for all of us in here.
In a post below https://mb.boardhost.com/historyroyaljewels/msg/1617782448.html
Paisley commented, "As Princess Margaretís diamond Cartier rose brooch wasnít on that list and there was no real information about it in the auction catalog other than it was 1938 Cartier London, Iíve always thought it was a Greville piece. She had it by the Coronation, so maybe a birthday present from her parents?"
That prompted me to finish a search I had started some time ago to find when, and how, Princess Margaret acquired this brooch.
Before I resumed, I double checked to make sure that no one had come up with the information, as I didn't want to waste time reinventing the wheel.
When the brooch was sold by Christie's in 2006 the only information given was that it had been made by Cartier, London in 1938.
See Christie's https://www.christies.com/en/lot/lot-4718176
The most notable occasion on which Princess Margaret wore this brooch was at the coronation of QEII in June 1953.
This has led some to speculate that the brooch was acquired for the coronation. It wasn't.
Princess Margaret began being photographed wearing the brooch in early December 1952, and from that time it became a favourite for day wear as well as evening and formal occasions.
Princess Margaret was wearing the brooch when members of the Royal family went to meet the Duke of Edinburgh and the Duchess of Kent on their return to London on 2 December 1952.
Later in the month, when the family left London for Sandringham, Princess Margaret again wore the brooch for the trip.
The Princess again wore the brooch several times before I found the clue to its origin. That came from the information about the wedding of the Earl of Dalkeith on 10 January 1953.
According to the press the Princess was wearing --
Numerous photos attest that the jewel was the one we are discussing.
Princess Margaret at the Dalkeith wedding in 1953.
The brooch was presented to Princess Margaret when she launched the Maori for the Union Steamship company of New Zealand at the Vickers Armstrong Naval Yard at Walker-on-Tyne on 27 November 1952.
It was described in the press as --
Despite the second description mentioning roses, I have no doubt that the Cartier rose brooch is the one which was presented to Princess Margaret.
Even though Princess Margaret didn't wear a brooch for the launch, she does not appear to have pinned it to her coat immediately. (I couldn't find a photo of her leaving)
According to the catalogue from the Cartier exhibition in Canberra in 2018 the Rose brooch is today in the Cartier collection, so hopefully we will see it again in future exhibitions.