Queen Silvia has worn the big Braganza tiara for every welcome dinner for incoming State Visits from foreign Royals to Sweden ever since Queen Elizabeth's State Visit to Sweden in 1983.
The big (and surprising) exception was the Jordanian state visit to Sweden.
She has never worn it to the Nobel ceremony, and never worn it abroad.
Apart from these occasions, Queen Silvia has only worn it for official photographs.
Regarding the Six Button tiara: Queen Silvia has worn it only ONCE, on January 29, 2004, for one of the annual Gala Dinners which take place the beginning of every year. There's a photo of it in the 'Bildarkiv' section of the official Swedish Royal family royalcourt.se, here's the link (hope it works): http://www.royalcourt.se/aktuellt/bi...7fff21882.html