What is a gem species based on?

A gem species is defined primarily by its crystal structure and chemical composition. This classification is fundamental because it provides a systematic way to group gemstones that share similar physical and chemical properties. For instance, all diamonds belong to the diamond species, characterized by their specific carbon atomic structure and properties.

In contrast, color and clarity, while important for determining a gemstone's quality and value, do not define its species. They are traits observed within a species but don’t categorize the gem itself. Similarly, cut and carat weight contribute to the stone's overall aesthetics and market value but do not affect the fundamental classification. The origin of a mineral can relate to the gemstone's market value or desirability but does not influence which species a gemstone belongs to. This is why the classification based on crystal structure and chemical composition is the most relevant aspect of a gem's species.