Like many other mints, the Royal Mint issues bullion coins in precious metals, having much higher intrinsic value than their face value. The five ounces (5 oz) gold coins are denominated as either ten pounds (£10) or five hundred pounds (£500).
The coins are legal tender but are not intended for circulation. They are targeted at bullion investors or collectors who appreciate the special editions as pieces of art. The coins are typically "one-year" types usually issued in parallel with smaller denominations with the same reverse designs.
This commemorative five ounce gold proof coin celebrates the 90th birthday of Queen Elizabeth II.
The Royal Mint says about the coin:
"Her Majesty The Queen has celebrated many landmark moments during her long and eventful reign birthdays, jubilees and wedding anniversaries and we have enjoyed each happy occasion with her. Now we celebrate with the Royal Family once again as Queen Elizabeth II becomes the first British monarch to reach a 90th birthday. As this much loved public figure reaches another remarkable milestone, at The Royal Mint we are delighted to release a commemorative coin for the occasion. To wish Her Majesty every happiness as royal history is made, acclaimed artist Christopher Hobbs has turned to her love of flowers for inspiration, his design approved by The Queen herself. As this is a more personal occasion, the artist has filled the classical wreath with natural rather than heraldic roses, with each one different to the next." | 
Search for United Kingdom: Gold Five Ounces 2016 Queen's 90th Birthday on eBay 