The two most popular focal stone colors in jewelry are red and blue. Spinel occurs in red and blue hues that rival those of the finest rubies and sapphires.

In fact, it was not until the mid-1800s that European scientists and gem dealers learned that spinel and ruby were two different minerals. Before then, several spectacular spinels were used in the crown jewels of monarchs.

The most stunning example of a spinel being mistaken for ruby is a gem known as “The Black Prince’s Ruby”. It is actually a spinel mounted as the primary focal stone of the Imperial State Crown – part of the Crown Jewels of the United Kingdom.