Coyamito Agate is a highly sought-after variety of chalcedony known for its stunning, vivid color bands and intricate 'fortification' patterns. It is found exclusively in volcanic rhyolite nodules in the Chihuahua region of Mexico, where collectors prize it for its high translucency and unique pinks and reds.
Is this coyamito 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 coyamito agate with a known reference. Coyamito 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. Coyamito Agate leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Coyamito Agate typically shows a waxy luster.
- 4Match the color rangeCompare against the expected color range: red, white, pink, orange, brown.
- 5Look at form & habitCrystal system: trigonal. Typical habit: botryoidal.
Often confused with
Coyamito Agate vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside coyamito agate
Minerals reported to co-occur with coyamito 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 g/cm³
- Streak
- White
- Luster
- Waxy
- Transparency
- Translucent
- Crystal system
- Trigonal
- Crystal habit
- Botryoidal
- Cleavage
- None
- Rarity
- Uncommon
- Uses
- Lapidary, Collector, Decorative
- Host rock
- Rhyolite Cavities
- Typical price
- $20-200 depending on banding quality and size
Where rockhounds find coyamito agate
Classic worldwide localities
- Villa Ahumada, Chihuahua, Mexico
Field-hunting tip
Look in rhyolite cavities country — that is the host setting where coyamito agate typically forms. If you start seeing quartz, calcite, hematite 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.
Common questions
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Find coyamito agate on the map
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