For thousands of years, terms such as rubies, sapphires, gems, and jewels have been in our vocabulary. However, some find defining a gem quite challenging. Most gems are minerals, but some, notably pearl and amber, are organics. Living organisms create these materials. By definition, a mineral must be created inside the earth. (To add some confusion, a pearl’s coating is a mineral though it’s created in a mollusk). Hence, pearls fall into a different category. Likewise, amber began life as tree sap. After millions of years, it transformed into a polymer, a natural plastic. People have regarded amber as a gem for thousands of years, although it’s definitely not a mineral.