Thank you, Crisitina, for this beautiful (and probably not exhaustive) insight into Queen Sofia's jewel collection. A very large collection, reflecting not only official gifts, but also probably Queen Sofia's own artistic tastes.
I am puzzled by another brooch worn very rarely by Queen Sofia : a ten-pointed starburst brooch, with diamond collets between each point:
I think this could be this brooch, here worn on her corsage by Queen Maria-Cristina:
Has anyone other pictures of this beautiful classical brooch, either on Queen Sofia, or on any other royal lady?