What is the definition of a gem?Ī gem is a stone that is considered precious or semi-precious, particularly when it is polished or cut. Read on to discover the legends associated with some of the world’s most treasured jewels. We’ve all heard that diamonds symbolize true love, but what are the symbolic meanings of other popular gemstones? From ancient times to today, gems of every hue have been imbued with significance and special powers by cultures around the world.