Fairfield Agate is a variety of chalcedony renowned for its unique, often landscape-like banded patterns and earth-tone coloration. It is typically found as nodules within volcanic tuff deposits in Utah and is highly prized by lapidary artists for cabochon cutting.
Is this fairfield 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 fairfield agate with a known reference. Fairfield 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. Fairfield Agate leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Fairfield Agate typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: brown, tan, white, black, gray.
- 5Look at form & habitCrystal system: trigonal. Typical habit: nodular.
Often confused with
Fairfield Agate vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Luster reads vitreous on Fairfield Agate and waxy on Flint Nodules.
How to tell apart: Luster reads vitreous on Fairfield Agate and waxy on Jasper.
How to tell apart: Luster reads vitreous on Fairfield Agate and waxy on Chalcedony.
Often found alongside fairfield agate
Minerals reported to co-occur with fairfield 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
- Vitreous
- Transparency
- Translucent
- Crystal system
- Trigonal
- Crystal habit
- Nodular
- Cleavage
- None
- Rarity
- Common
- Uses
- Lapidary, Collector
- Host rock
- Sedimentary Volcanic Tuffs
- Typical price
- $5-50 depending on size and patterns
Where rockhounds find fairfield agate
1 mapped spotsClassic worldwide localities
- Fairfield, Utah
- Cedar Mountains, Utah
- Tooele County, Utah
Field-hunting tip
Look in sedimentary volcanic tuffs country, the host setting where fairfield agate typically forms. If you start seeing calcite, quartz, goethite 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 South Dakota. Start trip planning there.
Common questions
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Find fairfield agate on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
