A silicified fern forms when ancient fern tissue is replaced molecule by molecule by silica-rich water over geological time, turning plant matter into stone. Look for intricate, detailed venation within the matrix, often preserved in shades of brown or grey from mineral impurities. It is popular in lapidary work for cabochons and display pieces thanks to its striking organic detail.
Is this silicified fern?
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 silicified fern with a known reference. Silicified Fern 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. Silicified Fern leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Silicified Fern typically shows a vitreous to waxy luster.
- 4Match the color rangeCompare against the expected color range: brown, black, gray, tan, red, yellow.
- 5Look at form & habitCrystal system: trigonal. Typical habit: pseudomorphous.
Often confused with
Silicified Fern vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside silicified fern
Minerals reported to co-occur with silicified fern. 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
- 2.5-2.7 g/cm³
- Streak
- White
- Luster
- Vitreous to Waxy
- Transparency
- Opaque
- Crystal system
- Trigonal
- Crystal habit
- Pseudomorphous
- Cleavage
- None
- Rarity
- Common
- Uses
- Lapidary, Collector, Decorative
- Host rock
- Sedimentary Strata
Where rockhounds find silicified fern
1 mapped spotsClassic worldwide localities
- Arizona, USA
- Madagascar
- Germany
- Czech Republic
- Wyoming, USA
Field-hunting tip
Look in sedimentary strata country, the host setting where silicified fern typically forms. If you start seeing quartz, chalcedony, pyrite in float, you are in the right ground. Field specimens usually show a pseudomorphous habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Nebraska. Start trip planning there.
More silicified fern photos
Common questions
How do you identify silicified fern?+
Where is silicified fern found?+
Can I find silicified fern in the United States?+
What rocks look like silicified fern?+
What minerals are found with silicified fern?+
What kind of rock does silicified fern form in?+
What is silicified fern used for?+
Find silicified fern on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
