Sea urchin fossils are the preserved remains of echinoids, typically characterized by their distinctive radial symmetry and five-fold pattern. They are most commonly found in marine sedimentary deposits like chalk or limestone, often replaced by silica or calcite during the fossilization process.

Hardness

3-5

Mohs

Luster

Dull

Streak

White

Transparency

Opaque

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Sea Urchin Fossil

Also: Echinoid Fossil

Hardness: 3-5
Luster: Dull
Streak: White
Transparency: Opaque

Is this sea urchin fossil?

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 sea urchin fossil with a known reference. Sea Urchin Fossil sits at Mohs 3-5, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Sea Urchin Fossil leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Sea Urchin Fossil typically shows a dull luster.
4
Match the color range
Compare against the expected color range: white, gray, tan, brown, reddish.
5
Look at form & habit
Typical habit: massive.

Often found alongside sea urchin fossil

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

All properties

Mohs hardness: 3-5
Density: 2.5-2.7 g/cm³
Colors: White Gray Tan Brown Reddish
Streak: White
Luster: Dull
Transparency: Opaque
Crystal habit: Massive
Cleavage: None
Rarity: Common
Uses: Collector, Decorative
Host rock: Sedimentary Limestone or Chalk
Typical price: $5-50 for common specimens, $100+ for rare species or matrix pieces.

Where rockhounds find sea urchin fossil

Classic worldwide localities

France
United Kingdom
Morocco
United States
Poland

Field-hunting tip

Look in sedimentary limestone or chalk country, the host setting where sea urchin fossil typically forms. If you start seeing calcite, quartz, pyrite 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.

Common questions

How do you identify sea urchin fossil?+

Mohs hardness is 3-5. It typically shows a dull luster. The streak is white. Common colors include white, gray, tan, brown.

Where is sea urchin fossil found?+

Notable localities include France; United Kingdom; Morocco; United States; Poland.

How much is sea urchin fossil worth?+

Typical asking prices fall in the range of $5-50 for common specimens, $100+ for rare species or matrix pieces.. Quality, size, and provenance can move individual specimens well outside that range.

What minerals are found with sea urchin fossil?+

Sea Urchin Fossil commonly co-occurs with Calcite, Quartz, Pyrite, Flint. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does sea urchin fossil form in?+

Sea Urchin Fossil typically forms in sedimentary limestone or chalk. Working float back to the host body is the standard way to chase a fresh occurrence.

What is sea urchin fossil used for?+

Sea Urchin Fossil is used in collector, decorative.

Find sea urchin fossil on the map

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