Plume agate is a microcrystalline variety of quartz characterized by feathery, plume-like inclusions of various minerals, typically iron or manganese oxides. It is highly sought after by lapidary artists due to the intricate, three-dimensional internal patterns that appear when cut and polished. Collectors usually find these in nodules or geodes within basaltic volcanic deposits.
Is this plume agate?
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 plume agate with a known reference. Plume Agate 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. Plume Agate leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Plume Agate typically shows a waxy luster.
- 4Match the color rangeCompare against the expected color range: white, gray, brown, red, yellow, orange.
- 5Look at form & habitCrystal system: trigonal. Typical habit: massive.
Often confused with
Plume Agate vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside plume agate
Minerals reported to co-occur with plume agate. 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
- Waxy
- Transparency
- Translucent
- Crystal system
- Trigonal
- Crystal habit
- Massive
- Cleavage
- None
- Rarity
- Common
- Uses
- Lapidary, Collector, Decorative
- Host rock
- Volcanic Cavities and Hydrothermal Veins
- Typical price
- $10-100 per rough specimen, $50-500+ for high-quality finished cabs
Where rockhounds find plume agate
5 mapped spotsClassic worldwide localities
- Oregon
- Idaho
- Montana
- Mexico
- Brazil
Field-hunting tip
Look in volcanic cavities and hydrothermal veins country — that is the host setting where plume agate typically forms. If you start seeing quartz, opal, jasper in float, you are in the right ground. Field specimens usually show a massive habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Texas, Idaho, Oregon — start trip planning there.
Common questions
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Find plume agate on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
