I also had a look at the Royal-Magazine website and found an entry regarding this brooch. The brooch is rather a mystery, so if Lady Helen is reading this board maybe she could help us get to the bottom of this...

If I understood the information correctly, on Royal-Magazine it says that this brooch belonged to Queen Mary and that it was used as a clasp for one of her bracelets.

But I have also seen information "out there" on the net that the brooch was a gift to Princess Marina for launching a ship in 1954.

And there is no agreement on when this brooch ended up with the late Duchess of Kent either. Some say that it was a gift to the Duchess on the birth of her daughter Lady Helen. Others say that it was inherited by the Duchess when her mother-in-law died in 1968. But if we have seen Katharine wearing this brooch both on the photos of the birth of her eldest son and that of her daughter two years later it doesn't really add up.