# Opulent Opal (DD-169)

> Opal is hydrated amorphous silica. Precious opal shows play-of-color, flashes of spectral color that shift with the viewing angle, while common opal doesn't. The effect comes from diffraction: precious opal is built from tiny silica spheres packed in a regular lattice, and their size and spacing set which colors appear. Australia produces most of the world's precious opal. Folklore around opals ranges from good luck to bad luck. The footage shows polished and rough opals, with the presenter.

- Department: Science (also Nature)
- First published: 2024-01-08
- Last updated: 2024-01-08
- Permalink: https://detailenjoyer.com/case/opulent-opal/
- Author: Marcus Easterling (DetailEnjoyer), The Detail Department

## Quick facts

- **DD-169-F01**: Opal is hydrated amorphous silica. _(Write-up · Exhibit A (Amorphous silica))_
- **DD-169-F02**: Precious opal shows play-of-color. _(Write-up · Exhibit B (Play-of-color))_

## Write-up

Opal's colors come from tiny stacked spheres of silica. The spheres diffract light like a grating.

1. **Amorphous silica**: Opal is hydrated amorphous silica.
2. **Play-of-color**: Precious opal shows play-of-color.
3. **Silica spheres**: Packed silica spheres diffract light.
4. **Sphere size**: Sphere size and spacing set the colors.
5. **Australia**: Australia produces most precious opal.

## Related case files

- [No Perfect Crystallizations (DD-288)](https://detailenjoyer.com/case/no-perfect-crystallizations/): I linked more about minerals
- [Quartz Crystals (DD-168)](https://detailenjoyer.com/case/quartz-crystals/): I linked another form of silica

## Reel vs. record

- **Note**: None needed.

## Video: Opulent Opal: Opal's Colors Come From Tiny Stacked Spheres of Silica

- Duration: 43.2 s · Published: 2024-01-08
- File: https://detailenjoyer.com/assets/videos/C13IGtYNyXJ.mp4

### Transcript

Opal is a mesmerizing gemstone renowned for its play of color a phenomenon where it displays vibrant flashes of iridescence that change with the viewing angle. DID YOU KNOW? This captivating optical effect is created by the diffraction of light as it interacts with silica spheres within the stone. Opals come in a spectrum of colors and their beauty lies in the unique patterns and combinations of hues they exhibit. The play of color can include shades of orange, green, blue, and violet, making opals one of the most colorful Beyond their aesthetic appeal opals have been surrounded by myths and Some cultures believed opals brought good luck while others considered them symbols of hope. Regardless of superstitions opals remain highly prized in the world of for their unique and ever-changing beauty. NOW YOU KNOW!

## Questions & answers

**Q: What is opal made of?**  
A: It's amorphous. _(Source: Write-up · Exhibit A (Amorphous silica) · Wikipedia: Opal)_

**Q: What is opal's color flash called?**  
A: It shifts with angle. _(Source: Write-up · Exhibit B (Play-of-color) · Wikipedia: Opal)_

**Q: What causes it?**  
A: A natural grating. _(Source: Write-up · Exhibit C (Silica spheres) · Wikipedia: Opal)_

**Q: What sets the colors?**  
A: Bigger spheres show reds. _(Source: Write-up · Exhibit D (Sphere size) · Wikipedia: Opal)_

**Q: Which country produces most precious opal?**  
A: Most of the world's supply. _(Source: Write-up · Exhibit E (Australia) · Wikipedia: Opal)_

## Sources

- [Wikipedia: Opal](https://en.wikipedia.org/wiki/Opal)

## Cite this case file

Easterling, Marcus. "Opulent Opal." The Detail Department (DetailEnjoyer), case file DD-169, last updated Jan 8, 2024. https://detailenjoyer.com/case/opulent-opal/