The Queen loaned the Cartier Halo Scroll Tiara to Kate Middleton for her wedding day. It was originally commissioned by George VI as a gift for his wife in 1936. She then passed it down to her daughter Princess Elizabeth (soon to be Queen Elizabeth II), as an 18th birthday gift, and it's believed to have been the first tiara the queen owned. The tiara is made up of almost 1,000 diamonds (739 brilliant-cut diamonds and 149 baguette diamonds) set in platinum.