Horse Mountain Agate is a highly sought-after variety of microcrystalline quartz known for its vibrant red to orange banding and occasional plume-like inclusions. It typically forms within the vesicles of volcanic rhyolite and is prized by lapidary artists for its ability to take a high polish. Collectors should look for specimens with distinct fortification patterns and high translucency.
Is this horse mountain 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 horse mountain agate with a known reference. Horse Mountain 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. Horse Mountain Agate leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Horse Mountain Agate typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: red, orange, yellow, white, clear.
- 5Look at form & habitCrystal system: trigonal. Typical habit: botryoidal.
Often confused with
Horse Mountain Agate vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Luster reads vitreous on Horse Mountain Agate and vitreous to waxy on Carnelian.
How to tell apart: Luster reads vitreous on Horse Mountain Agate and waxy on Jasper.
How to tell apart: Luster reads vitreous on Horse Mountain Agate and waxy on Fire Agate.
Often found alongside horse mountain agate
Minerals reported to co-occur with horse mountain 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
- 2.65 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Trigonal
- Crystal habit
- Botryoidal
- Cleavage
- None
- Rarity
- Uncommon
- Uses
- Lapidary, Collector, Decorative
- Host rock
- Volcanic Rhyolite
- Typical price
- $10-100 per specimen
Where rockhounds find horse mountain agate
1 mapped spotsClassic worldwide localities
- Horse Mountain, Humboldt County, Nevada, USA
Field-hunting tip
Look in volcanic rhyolite country — that is the host setting where horse mountain agate typically forms. If you start seeing quartz, opal, chalcedony 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 Tennessee — start trip planning there.
Common questions
How do you identify horse mountain agate?+
Where is horse mountain agate found?+
Can I find horse mountain agate in the United States?+
How much is horse mountain agate worth?+
What rocks look like horse mountain agate?+
What minerals are found with horse mountain agate?+
What kind of rock does horse mountain agate form in?+
What is horse mountain agate used for?+
Find horse mountain agate on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
