October Birthstone: Opal - Color & Meaning | The Old Farmer's Almanac

October Birthstone: Opal

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All About Opal: Color, Meaning, and Folklore

Martie Majoros
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October’s birthstone, the opal, symbolizes faithfulness and confidence. The word comes from the Latin opalus, meaning “precious jewel,” and from the Greek word opallios, meaning “to see a change in color.” Discover more about this month’s birthstone!

What Is Opal?

Opals are a type of quartz made up of tiny spheres of amorphous hydrated silica, which give it its rainbow shimmer.

Opal’s high water content makes it prone to cracking or crazing (many fine cracks), however. This can happen if the gem dries out, such as might occur when exposed to high temperatures or long periods of low humidity. The gem is relatively soft, with a hardness rating of only 5.5. (Never place an opal in an ultrasonic jewelry cleaner: The vibrations can crack the gem.) 


October Birthstone Color

When light hits the sphere structures in opal, the colors of the visible spectrum appear. In different lights, an opal’s rainbow fragments may shift and change, revealing luminous bright and dark colors for a fascinating display. 

Opal Facts & Folklore

  • Australian aboriginal tribes believed that opals were the Creator’s footprints on Earth.
  • Necklaces with opals set in them were traditionally worn to repel evil and to protect eyesight. 
  • Opals are said to control one’s temper and calm nerves.
  • A dream of an opal means that good luck will come.

Alternative October Birthstone: Tourmaline

The other October birthstone, tourmaline, comes in a kaleidoscope of colors; often more than one hue is present in a gem. Brightly colored specimens are valued more highly.

When heated or cooled, these gems develop an electric charge; the Dutch once used them to remove ash from meerschaum tobacco pipes.

Egyptian legend says that tourmaline received its colors as it passed through a rainbow on its way up from Earth’s core. The gem symbolizes inspiration and once was believed to protect against evil.


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