The Three Thistle BroochThis brooch features three of Scotland's signature bloom, the thistle. It appears to be composed of diamonds set in yellow gold on the leaves and a white/silver metal for the thistles - the glitter from the piece in action lets us know that it certainly has sparkle power. When the Queen wore it to the Commonwealth Games in 2014, the Press Association reported that it was one of a set of four pins given to her by the Sultan of Oman; it would be natural to guess that the other three pins might represent other parts of the United Kingdom, though this was not detailed*. The thistle pin made its first public appearance during 2012's Holyrood Week, so perhaps it was part of a gift given for the Diamond Jubilee.
*Other potential candidates for the other three pins from the Sultan of Oman, simply pulling possibilities from brooches that have appeared in recent years and share design characteristics and/or a possible national theme (none confirmed, all speculation): Daffodil Spray Brooch, Rose Gold Brooch, Tudor Rose Brooch, Shamrock Brooch, Irish Blossom Brooch. All of these first appeared in 2012/2013, with the exception of the Irish Blossom which appeared in 2009.
6 September 2015: Church at Balmoral
20 June 2015: Royal Ascot, Day 5
24 July 2014: Commonwealth Games Visit
1 July 2014: Harry Benson Portrait
1 October 2013: Visit to Aberdeen
27 September 2012: Ballater Jubilee Cairn
2 July 2012: Holyrood Week, Day 1