The Queen wore it to receive the Archbishop of Canterbury and the Grand Imam of Al-Azhar.
In a detailed string of tweets, one social media user explained the significance of the brooches worn by the Queen earlier this month during a visit from U.S. President Donald Trump, alleging that it's no coincidence she wore brooches given to her by Barack and Michelle Obama and another given by Canada. It is also known as the American State Visit brooch. Her Majesty 1 His Tangerineness 0. The same brooch that Liz wore again at a subsequent dinner with the Obamas at Winfield House in London. Considering the vast size of the Monarch's collection of glittering brooches - a signature accessory of hers - the choice to wear a piece presented to her by the Obamas seems far from coincidental.
In that meeting, Mr. Trump may have also committed a royal faux pas by momentarily walking in front of Queen Elizabeth as she reviewed the guard. Reportedly, the blue dress had a floral piece brooch, which was a personal gift from former US President Barack Obama and former First Lady Michelle Obama during their 2011 state visit.
Mr. Trump walked alongside the queen as she inspected the Honor Guard at Windsor Castle on Friday.
Queen Elizabeth II poses with King Philippe of Belgium and Queen Mathilde of Belgium at Windsor Castle.
According to Her Majesty's Jewel vault the small green flower brooch was selected it from the vintage selection at the Tiny Jewel Box jewelry store in Washington, D.C by the former president and First Lady in 2011.
The Queen's snowflake brooch features 48 sapphires mined from Canada's Baffin Island. On the day Air Force One landed in the United Kingdom last week, the queen accessorized with a green flower brooch, made of 14 karat yellow gold and diamonds.
While welcoming her American guest to tea the Queen wore perhaps the most controversial badge of all.
A closer look at the Queen's diamond palm leaf brooch.
The Queen inherited the brooch in 2002.
Watch Blue Origin's high-altitude abort test during latest rocket launch
On Wednesday's flight, Blue Origin says it will push the New Shepard rocket to its limits with a high-altitude escape motor test. The company has yet to start selling tickets for the vehicle and has not established an official price for those flights.