|Example of the cap badge. The brooches use the central leek only.|
And The Queen's version isn't the only leek badge in the royal family, either. While still married to Prince Charles, the late Diana, Princess of Wales wore a version that also appears to have been set in diamonds (you can see more views at the Princess Diana Remembered site).
7 July 2016: Visit to Wales (Duchess of Cornwall)
30 April 2015: Welsh Guards New Colours Presentation (Queen and Duchess of Cornwall)
Photos: via Getty Images and Wikimedia Commons/British Army