Baculites are extinct cephalopods characterized by their straight, rather than coiled, chambered shells. Collectors typically find them as fossils within marine shales and limestones, often with intricate suture patterns visible on the exterior when the outer shell layer has eroded.

Hardness

3-4

Mohs

Luster

Dull

Streak

White

Transparency

Opaque

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Baculite

Hardness: 3-4
Luster: Dull
Streak: White
Transparency: Opaque

Is this baculite?

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 baculite with a known reference. Baculite sits at Mohs 3-4 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Baculite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Baculite typically shows a dull luster.
4
Match the color range
Compare against the expected color range: brown, gray, beige, white.
5
Look at form & habit
Typical habit: straight cephalopod shell.

Often confused with

Baculite vs. its common look-alikes — and how to tell them apart in the field.

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Belemnite

Mohs 3-4

How to tell apart: Luster reads dull on Baculite and dull to waxy on Belemnite.

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Often found alongside baculite

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

All properties

Chemical formula: CaCO₃
Mohs hardness: 3-4
Density: 2.6-2.9 g/cm³
Colors: Brown Gray Beige White
Streak: White
Luster: Dull
Transparency: Opaque
Crystal habit: Straight Cephalopod Shell
Cleavage: None
Rarity: Common
Uses: Collector, Educational
Host rock: Marine Sedimentary Rock
Typical price: $5-100 per specimen

Where rockhounds find baculite

Classic worldwide localities

South Dakota, USA
Wyoming, USA
Montana, USA
Alberta, Canada
France

Field-hunting tip

Look in marine sedimentary rock country — that is the host setting where baculite typically forms. If you start seeing calcite, pyrite, aragonite in float, you are in the right ground. Field specimens usually show a straight cephalopod shell habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify baculite?+

Mohs hardness is 3-4. It typically shows a dull luster. The streak is white. Common colors include brown, gray, beige, white.

Where is baculite found?+

Notable localities include South Dakota, USA; Wyoming, USA; Montana, USA; Alberta, Canada; France.

How much is baculite worth?+

Typical asking prices fall in the range of $5-100 per specimen. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like baculite?+

Baculite is most often confused with Belemnite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with baculite?+

Baculite commonly co-occurs with Calcite, Pyrite, Aragonite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does baculite form in?+

Baculite typically forms in marine sedimentary rock. Working float back to the host body is the standard way to chase a fresh occurrence.

What is baculite used for?+

Baculite is used in collector, educational.

Find baculite on the map

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