How is the color of an idiochromatic gem determined?

The color of an idiochromatic gem is determined by the elements that are part of its chemical composition. Idiochromatic gems have inherent color due to the presence of specific elements within their structure, which absorb certain wavelengths of light and reflect others, resulting in their unique coloration. For instance, the presence of chromium in emeralds gives them their green color, while the presence of iron can impart a different hue.

This characteristic distinguishes idiochromatic gems from allochromatic gems, where color arises from impurities or different trace elements. In the case of allochromatic gems, variations in color are often a result of external factors, such as the presence of additional elements or treatments, rather than being an intrinsic property of the mineral itself. Therefore, the inherent nature of idiochromatic gems means their color is tightly linked to their specific chemical makeup.