Appearance
Look at the stone from several angles. Choose a pattern and body color you enjoy, rather than relying on one photograph or color label.
Opal
Shifting color and individual patterns make every opal feel different.
Precious opal displays play-of-color as light interacts with its structure. Not every opal shows this effect.
- Material
- Hydrated silica
- Birthstone
- October
- Mohs hardness
- 5–6.5
Understanding the color
Opal’s play-of-color results from diffraction by ordered microscopic silica spheres. Body color, brightness, pattern, and the colors visible as the stone moves all contribute to its appearance. A red flash does not guarantee that every other color is present.
Learn more: GIA: Opal
Choosing your opal
Construction and condition
Ask whether the piece contains a solid opal or an assembled doublet or triplet. Review treatments, cracks, and the condition of the surface; construction affects care.
Learn more: GIA: qualities to consider
Types of opal
White, black, boulder, crystal, and fire opal describe different appearances or structures. Fire opal refers to a yellow, orange, or red body color and may occur with or without play-of-color.
Learn more: GIA: types of opal
Care
Opal is relatively delicate. Protect it from scratches, impacts, high heat, and sudden temperature changes. Avoid ultrasonic and steam cleaning. For solid opal, use gentle cleaning with warm, soapy water; follow specific advice for assembled or treated pieces rather than soaking them.
Learn more: GIA: care and cleaning
Find the right piece for you.
We can help you compare materials, choose a gemstone, and understand how to care for your jewelry.