Blue Agate geodes feature striking concentric banding in shades of sky blue, often with a sparkling quartz crystal lining inside the hollow center. These specimens are typically found within volcanic basalt cavities where silica-rich fluids have slowly deposited layers over time. They are a favorite among collectors for their vibrant color and the dramatic contrast between the banded exterior and crystalline interior.
Is this blue agate geode?
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 blue agate geode with a known reference. Blue Agate Geode sits at Mohs 6.5-7, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Blue Agate Geode leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Blue Agate Geode typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: blue, white, gray, lavender.
- 5Look at form & habitCrystal system: trigonal. Typical habit: botryoidal.
Often confused with
Blue Agate Geode vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside blue agate geode
Minerals reported to co-occur with blue agate geode. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- SiO₂
- Mohs hardness
- 6.5-7
- Density
- 2.6-2.7 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Trigonal
- Crystal habit
- Botryoidal
- Cleavage
- None
- Rarity
- Common
- Uses
- Collector, Lapidary, Decorative
- Host rock
- Sedimentary Basalt Cavities
- Typical price
- $10-100 for small nodules, $200+ for large polished geodes
Where rockhounds find blue agate geode
1 mapped spotsClassic worldwide localities
- Brazil
- Uruguay
- USA (Montana)
- Botswana
Field-hunting tip
Look in sedimentary basalt cavities country, the host setting where blue agate geode typically forms. If you start seeing quartz, calcite, goethite 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 Washington. Start trip planning there.
Common questions
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Find blue agate geode on the map
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