A fossilized fern is the preserved remains or impression of a prehistoric plant, found primarily in carbonaceous shale and siltstone. Collectors look for a high-contrast specimen where the organic carbon film has been preserved against a lighter or differently colored sedimentary matrix.

Hardness

3-6

Mohs

Luster

Dull

Streak

White

Transparency

Opaque

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Fossilized Fern

Also: Fern fossils, Pteridophyte fossils

Hardness: 3-6
Luster: Dull
Streak: White
Transparency: Opaque

Is this fossilized fern?

5-step field check

Run through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.

1
Test the hardness
Try to scratch fossilized fern with a known reference. Fossilized Fern sits at Mohs 3-6, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Fossilized Fern leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Fossilized Fern typically shows a dull luster.
4
Match the color range
Compare against the expected color range: black, brown, gray, tan.
5
Look at form & habit
Typical habit: imprint.

Often found alongside fossilized fern

Minerals reported to co-occur with fossilized fern. Spotting these in float or country rock is a strong cue you are in the right ground.

All properties

Mohs hardness: 3-6
Density: 2.5-2.7 g/cm³
Colors: Black Brown Gray Tan
Streak: White
Luster: Dull
Transparency: Opaque
Crystal habit: Imprint
Cleavage: None
Rarity: Common
Uses: Collector, Educational, Decorative
Host rock: Shale, Siltstone, Coal

Where rockhounds find fossilized fern

1 mapped spots

Classic worldwide localities

Mazon Creek, USA
Joggins, Canada
Czech Republic
Germany
France

Field-hunting tip

Look in shale, siltstone, coal country, the host setting where fossilized fern typically forms. If you start seeing pyrite, siderite, kaolinite in float, you are in the right ground. Field specimens usually show a imprint habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Oregon. Start trip planning there.

Browse 1 U.S. spots for fossilized fern →

More fossilized fern photos

Common questions

How do you identify fossilized fern?+

Mohs hardness is 3-6. It typically shows a dull luster. The streak is white. Common colors include black, brown, gray, tan.

Where is fossilized fern found?+

Notable localities include Mazon Creek, USA; Joggins, Canada; Czech Republic; Germany; France.

Can I find fossilized fern in the United States?+

RockHoundR maps 1 fossilized fern rockhounding spots across 1 U.S. states. The top states are Oregon.

What minerals are found with fossilized fern?+

Fossilized Fern commonly co-occurs with pyrite, siderite, kaolinite, quartz. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does fossilized fern form in?+

Fossilized Fern typically forms in shale, siltstone, coal. Working float back to the host body is the standard way to chase a fresh occurrence.

What is fossilized fern used for?+

Fossilized Fern is used in collector, educational, decorative.

Find fossilized fern on the map

RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.