Jorge what a wonderful idea! Since the Braganzas are not a rulling family and they are very discrete, their jewelry is not much discussed, sadly.
But I must start by stating that, to my knowledge, that is not Dona Isabel's engagement ring. When Dona Isabel was pregnant with her first son and heir, Afonso the Prince of Beira, she gave an interview to Caras magazine and she was wearing her engagement ring and talked about it. The engagement ring is a cabochon rubi, set on gold, and the ring had belong to Dom Duarte's grandmother, Elisabeth Dobrzensky de Dobrzenicz, mother of Duchess Dona Maria Francisca. Dona Isabel wore it often and the rubi ring was referred in the press at that time. I have no photo of it that I can post, I will dig and try to find some where the Duchess is wearing it.
That saphire ring appears in the book on the portuguese jewels, but I got the impression that it was a gift to celebrate the birth of Prince Afonso.
--Previous Message-- : For some reason the Braganza Family jewels are : not very known and when people talk about : them usually there is a lot of confusion. : For that reason I’m going to start a series : of threads about some of them. Hope you all : like. : : The first piece of jewellery I’m going to : talk about is D.Isabel engagement ring . : : This ring was made in gold by the house : ‘Leitão e Irmão’ (the Crown Jewelers) and : was commissioned by HRH D.Duarte. In one of : the sides it has 13 diamonds alluding to the : Dukes of Braganza wedding day (13th May – : also the day of Our Lady of Fatima). In the : other side it has the couple's monogram (D : from Duarte and I from Isabel) topped with a : royal crown. On the top it has white and : blue enamel (Portugal colors since its : foundation). Some literature says that the : enamel is white and black (the Heredia : Family colors). : : The following image was present in a : magazine a few years ago (sorry, I don't : remember which one) and circulated a lot : between the portuguese monarchists. : : : :