Silicified wood is a type of fossil where organic plant material has been completely replaced by microcrystalline silica, typically chalcedony, while retaining its original cellular structure. Collectors often look for high-contrast colors caused by mineral inclusions like iron or manganese and well-preserved growth rings. It is frequently found in sedimentary beds where trees were once buried in volcanic ash or mineral-rich groundwater.
Is this silicified wood?
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 wood with a known reference. Silicified Wood 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 Wood leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Silicified Wood typically shows a waxy to vitreous luster.
- 4Match the color rangeCompare against the expected color range: brown, red, yellow, white, black, gray.
- 5Look at form & habitTypical habit: massive.
Often confused with
Silicified Wood vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Luster reads waxy to vitreous on Silicified Wood and waxy on Agate.
How to tell apart: Luster reads waxy to vitreous on Silicified Wood and waxy on Jasper.
How to tell apart: Luster reads waxy to vitreous on Silicified Wood and waxy on Flint Nodules.
Often found alongside silicified wood
Minerals reported to co-occur with silicified wood. 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
- 2.6-2.7 g/cm³
- Streak
- White
- Luster
- Waxy to Vitreous
- Transparency
- Translucent
- Crystal habit
- Massive
- Cleavage
- None
- Rarity
- Common
- Uses
- Lapidary, Collector, Decorative
- Host rock
- Sedimentary Deposits
- Typical price
- $5-50 for small polished pieces, $100+ for large polished display specimens
Where rockhounds find silicified wood
41 mapped spotsClassic worldwide localities
- Arizona, USA
- Madagascar
- Indonesia
- Argentina
- Egypt
U.S. states with silicified wood
Each link opens a state-specific list of mapped rockhounding spots that produce silicified wood.
Field-hunting tip
Look in sedimentary deposits country — that is the host setting where silicified wood typically forms. If you start seeing quartz, chalcedony, hematite in float, you are in the right ground. Field specimens usually show a massive habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Wyoming, North Dakota, Montana — start trip planning there.
Common questions
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Find silicified wood on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
