A fossilized horse bone is the remains of an ancient equid preserved through permineralization, with minerals such as silica or calcite replacing the original bone material. It usually appears as a heavy, rock-like fragment that retains the porous internal structure of the original bone. It turns up in Cenozoic sedimentary layers and often takes careful identification to distinguish from local limestone or river cobbles.
Is this fossilized horse bone?
4-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 fossilized horse bone with a known reference. Fossilized Horse Bone sits at Mohs 3-6, softer than the next harder reference, harder than the previous one.
- 2Name the organismDecide what left the fossil before worrying about the rock. Organism: Horses and their ancestors (family Equidae). Age: About the last 50 million years; horses died out in North America about 10,000 years ago.
- 3Read the lusterHold the specimen under a strong light. Luster: dull to waxy.
- 4Match the color rangeCompare against the expected color range: brown, tan, white, gray, black.
Often confused with
Fossilized Horse Bone vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Luster reads dull to waxy on Fossilized Horse Bone and vitreous to waxy on Petrified Wood.
How to tell apart: Luster reads dull to waxy on Fossilized Horse Bone and vitreous; pearly on cleavages and {0001} on Calcite.
Often found alongside fossilized horse bone
Minerals reported to co-occur with fossilized horse bone. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Mohs hardness
- 3-6
- Density
- 2.0-3.0 g/cm³
- Luster
- Dull to waxy
- Transparency
- Opaque
- Rarity
- Common
- Uses
- Collector, Educational, Decorative
- Host rock
- sedimentary deposits
- Organism
- Horses and their ancestors (family Equidae)
- Age
- About the last 50 million years; horses died out in North America about 10,000 years ago
Where rockhounds find fossilized horse bone
1 mapped spotsClassic worldwide localities
- Badlands (USA)
- Hagerman Fossil Beds (USA)
- Florida (USA)
- Europe
- Asia
Field-hunting tip
Where it forms: sedimentary deposits. If you start seeing quartz, chalcedony, calcite in float, you are in the right ground. In the U.S., the densest reported localities are in California. Start trip planning there.
More fossilized horse bone photos
Common questions
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Find fossilized horse bone on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
