Dry Head Agate is a prized variety of chalcedony found in the Bighorn Canyon area known for its vibrant red, orange, and yellow fortification banding. Collectors typically hunt for these distinct, often rounded nodules that weather out of limestone and shale beds, frequently exhibiting exceptional contrast in their banding patterns.
Is this dry head 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 dry head agate with a known reference. Dry Head 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. Dry Head Agate leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Dry Head Agate typically shows a waxy luster.
- 4Match the color rangeCompare against the expected color range: red, orange, yellow, white, brown.
- 5Look at form & habitCrystal system: trigonal. Typical habit: nodular.
Often confused with
Dry Head Agate vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside dry head agate
Minerals reported to co-occur with dry head 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
- Nodular
- Cleavage
- None
- Rarity
- Uncommon
- Uses
- Lapidary, Collector, Decorative
- Host rock
- Chugwater Formation
- Typical price
- $10-100 per nodule depending on size and pattern
Where rockhounds find dry head agate
1 mapped spotsClassic worldwide localities
- Big Horn County, Montana
- Bighorn Canyon National Recreation Area, Wyoming
Field-hunting tip
Look in chugwater formation country — that is the host setting where dry head agate typically forms. If you start seeing calcite, hematite, quartz in float, you are in the right ground. Field specimens usually show a nodular habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Wyoming — start trip planning there.
Common questions
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Find dry head agate on the map
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