British Royal Jewellery items are a historic collection of jewels owned personally by the monarch of the Commonwealth realms This is currently Queen Elizabeth II. The origin of a royal jewel collection distinct from the official crown jewels is vague, though it is thought that the jewels have their origin somewhere in the sixteenth century. Many of the pieces are from all over the world and were brought back to the United Kingdom as a result of civil war, coups and revolutions, or acquired as gifts to the monarch. Source.
Below is a video that shows some great examples of the Royal collection.