Step 1: Introduction to Gemology
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. Not everyday people with common sense but people like lexicographers, who need to define each word in our language very precisely. I feel sorry for them, since simply no concise definition covers all the materials that have been regarded as gemstones throughout the centuries.
A Working Definition of a Gem?
The following definition covers the vast majority of the stones we regard as gems:
Minerals that have been chosen for their beauty and durability, then cut and polished for use as human adornment.
Still, every defining feature in that definition has exceptions. This creates problems.
Minerals vs. Organics
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…