Birds of a Feather: Sapphire & Ruby

Did you know that sapphire and ruby are essentially the same gemstone with different colors? That’s right, both sapphire and ruby belong to the gem species Corundum. Ruby is the red variety of corundum and, while most of us know sapphire as being blue, sapphire encompasses all the other colors of corundum.

The difference in color is due to trace elements within the corundum. Pure corundum is composed of only aluminum and oxygen and is colorless. But colorless corundum is very rare. If corundum has the trace element chromium, the crystal will be red and therefore will be a ruby. If corundum has the trace elements iron and titanium, the color will be blue, and therefore, blue sapphire. I will discuss the other colors of sapphire in future posts.

Author: Michelle M. Rahm is a GIA-trained Graduate Gemologist and is President of Colorado’s Mile High Chapter of the GIA Alumni Association. She has been selling gemstones and jewelry online since 1997. Visit her websites and

About mrahm

Michelle holds a Graduate Gemologist Diploma, Graduate Diamonds Diploma and Graduate Colored Stones Diploma through the Gemological Institute of America's distance education program. Michelle currently serves as President of the Mile High GIA Alumni Association. She also serves on the board of the Rocky Mountain Jeweler's Association and is a member of the American Gem Trade Association.
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