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Petrified wood is a fossil formed when organic plant matter is buried under sediment and replaced by silica through permineralization. Collectors look for well-preserved growth rings, bark texture, and vibrant colors caused by mineral impurities like iron and manganese.

Hardness
6.5-7
Mohs
Luster
Vitreous to Waxy
Streak
White
Transparency
Opaque

Spotting petrified wood in the field

Field marks
  • 1

    Visible grain, growth rings or bark texture preserved in stone

  • 2

    Heavy for its size, and stone-cold rather than wood-warm to the touch

  • 3

    Breaks with conchoidal fracture across the grain, not splintering along it

The giveaway is a piece that looks like a log but has the weight and ring of rock. Look at the end grain first, since rings and radial structure survive better than bark. Weathered exposures in badlands, road cuts and dry washes are the productive places, and desert varnish can disguise a beautiful piece as an ordinary brown rock, so check any broken face. Colors come from trace metals: red and yellow from iron, black from manganese and carbon, green rarely from chromium or copper.

Before you collect

Petrified Forest National Park is closed to collecting entirely, and this is enforced hard. Removing so much as a chip is a federal offense with real fines. BLM land outside the park boundary is open under the daily and annual limits, so a few hundred yards is the difference between a legal find and a citation.

Straight answers

Is it worth cutting?
Cut both ways. A cross-section shows rings and is the classic round face; a longitudinal cut shows the grain running the length of the slab. Porous or punky material needs stabilizing resin before it will hold a polish.
What is it really worth?
Common brown material is a few dollars a pound. Bright color, full rings, preserved bark, or limb sections with clean agate centers are where the value sits.
Can you legally keep it?
On BLM land, petrified wood has its own specific federal rule: up to 25 pounds plus one piece per person per day, capped at 250 pounds per year, for personal use only, and it may not be sold or bartered. Free-use collection cannot be done with power equipment or explosives.

Sources: BLM: Rockhounding and collecting on public lands

Often confused with

Petrified Wood vs. its common look-alikes, and how to tell them apart in the field.

Agatized Wood specimen - Polished slice of petrified wood
fossil
Agatized Wood
Mohs 6.5-7

How to tell apart: Not a different thing so much as a better one. Agatized wood is petrified wood where the replacement was chalcedony, giving it the hardness and polish that ordinary porous petrified wood lacks.

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Often found alongside petrified wood

Minerals reported to co-occur with petrified 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
Colors
BrownRedYellowBlackWhite
Streak
White
Luster
Vitreous to Waxy
Transparency
Opaque
Crystal habit
Pseudomorphous After Wood Structure
Cleavage
None
Rarity
Common
Uses
Lapidary, Collector, Decorative
Host rock
Sedimentary Strata
Typical price
$5-50 thumbnail, $50-500 cabinet specimen

Where rockhounds find petrified wood

227 mapped spots

Classic worldwide localities

  • Petrified Forest National Park, Arizona, USA
  • Madagascar
  • Argentina
  • Greece
  • Indonesia

U.S. states with petrified wood

Each link opens a state-specific list of mapped rockhounding spots that produce petrified wood.

Field-hunting tip

Look in sedimentary strata country, the host setting where petrified wood typically forms. If you start seeing quartz, chalcedony, goethite in float, you are in the right ground. Field specimens usually show a pseudomorphous after wood structure habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Oregon, Texas, Kansas. Start trip planning there.

Browse 227 U.S. spots for petrified wood →

More petrified wood photos

  • Petrified logs weathering out across badlands, the setting they are found in
  • Polished petrified wood showing growth rings and mineral colour

Common questions

How do you identify petrified wood?+
Mohs hardness is 6.5-7. It typically shows a vitreous to waxy luster. The streak is white. Common colors include brown, red, yellow, black.
Where is petrified wood found?+
Notable localities include Petrified Forest National Park, Arizona, USA; Madagascar; Argentina; Greece; Indonesia.
Can I find petrified wood in the United States?+
RockHoundR maps 227 petrified wood rockhounding spots across 12 U.S. states. The top states are Oregon, Texas, Kansas.
How much is petrified wood worth?+
Typical asking prices fall in the range of $5-50 thumbnail, $50-500 cabinet specimen. Quality, size, and provenance can move individual specimens well outside that range.
What rocks look like petrified wood?+
Petrified Wood is most often confused with Agatized Wood. A quick hardness test and a streak check separate the look-alikes faster than color alone.
What minerals are found with petrified wood?+
Petrified Wood commonly co-occurs with Quartz, Chalcedony, Goethite, Hematite. Spotting any of these in float or country rock is a useful trip signal.
What kind of rock does petrified wood form in?+
Petrified Wood typically forms in sedimentary strata. Working float back to the host body is the standard way to chase a fresh occurrence.
What is petrified wood used for?+
Petrified Wood is used in lapidary, collector, decorative.

Find petrified wood on the map

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

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