In ancient times all red stones were called rubies, all blue stones were called sapphires and all yellow stones were called topazes. It wasn't until 1783 that spinels could be differentiated from rubies. That was when some people started finding out that some of their treasures were not treasures at all. The most famous ruby that turned out to be a spinel was The Black Prince Ruby weighing 170 carats (34 g) set above the Cullinan II at the front of the Imperial State Crown. The spinel has been given to Edward of Woodstock (the "Black Prince") in 1367.