Lesson 26 · Gemstones & Earrings · 33 seconds
Why opal changes color when you tilt it
Precious opal shows play-of-color: tiny structures inside it interact with light, producing different colors as the viewing angle changes. A simplified picture is an orderly arrangement of tiny silica spheres; common opal does not show play-of-color.
What this lesson shows
Order inside the stone makes the color.
A labeled simplified model shows domains whose color follows the angle of light and view, then a greatly enlarged diagram of orderly stacked silica spheres sending one color back. Common opal's spheres are irregular, so it shows no play-of-color.
Three quick takeaways
What to actually do when you shop
- Play-of-color comes from tiny structures inside precious opal interacting with light.
- A simplified picture is an orderly arrangement of tiny silica spheres, far too small to see. Common opal does not show play-of-color.
- The movement is part of the beauty: tilt an opal to see its play-of-color.
The opal footage is AI-generated illustration, not a specific stone. The color model and sphere diagram are simplified and greatly enlarged, using typical published values. The narration uses an AI-generated voice. Captions are shown in the video.
Read the transcript
Tilt a precious opal, and the colors can shift. That effect is called play-of-color. Tiny structures inside it interact with light, producing different colors as the viewing angle changes. A simplified picture is an orderly arrangement of tiny silica spheres, far smaller than you can see here. Common opal does not show play-of-color. The movement is part of the beauty. Explore more in the Aydins Jewelry Learning Center.
Sources
- GIA, opal description: www.gia.edu/opal-description
- GIA, opal quality factors: www.gia.edu/opal-quality-factor
Related lessons
Same diamond, three lights · how light changes what you see.
Push backs and screw backs · how earring backs work.
From a diamond seed to a finished stone · how lab-grown diamonds are grown.
Next step
Keep learning.
More short lessons on gems and jewelry are in the Learning Center.