Banded Opal is a variety of common opal that exhibits distinct, parallel color bands due to rhythmic deposition of silica-rich fluids. It lacks the characteristic play-of-color found in precious opal, but is highly prized by lapidary artists for its smooth texture and unique layering. It is typically found in volcanic cavities or as a replacement material in sedimentary rock environments.
Is this banded opal?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch banded opal with a known reference. Banded Opal sits at Mohs 5.5-6.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Banded Opal leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Banded Opal typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: white, gray, brown, black, orange.
- 5Look at form & habitCrystal system: amorphous. Typical habit: botryoidal.
Often confused with
Banded Opal vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside banded opal
Minerals reported to co-occur with banded opal. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- SiO₂·nH₂O
- Mohs hardness
- 5.5-6.5
- Density
- 1.9-2.2 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Amorphous
- Crystal habit
- Botryoidal
- Cleavage
- None
- Fluorescence
- Often Green or White Under UV
- Rarity
- Common
- Uses
- Lapidary, Collector, Decorative
- Host rock
- Volcanic Rhyolite, Sedimentary Claystones
- Typical price
- $10-100 per piece depending on quality and pattern
Where rockhounds find banded opal
1 mapped spotsClassic worldwide localities
- Mexico
- Peru
- Australia
- USA
- Ethiopia
Field-hunting tip
Look in volcanic rhyolite, sedimentary claystones country — that is the host setting where banded opal typically forms. If you start seeing quartz, chalcedony, montmorillonite in float, you are in the right ground. Field specimens usually show a botryoidal habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Idaho — start trip planning there.
Common questions
How do you identify banded opal?+
Where is banded opal found?+
Can I find banded opal in the United States?+
How much is banded opal worth?+
What rocks look like banded opal?+
What minerals are found with banded opal?+
What kind of rock does banded opal form in?+
What is banded opal used for?+
Find banded opal on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
