|Frequently Asked Questions (FAQ) / Gemstone Color|
How do gemstones get their color?
There are several different reasons why the various gemstone varieties absorb light differently. Some gemstones are said to be idiochromatic or "self-colored", meaning that they absorb certain wavelengths of light due to characteristics of their chemical structure. Peridot, which contains iron, is an example of an idiochromatic gemstone.
However, idiochromatic gemstones are rare. Most gemstones are allochromatic, meaning that they are colored by impurities or trace elements in their crystal structure. For example, pure corundum is colorless. But corundum is typically red when traces of chromium are present; and blue when there are traces of titanium. We call the former ruby, and the latter sapphire. For more information, see our article on how gemstones get their colors.
- First Published: February-20-2006
- Last Updated: November-10-2014
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