Bryozoans are small, aquatic invertebrate colonial animals that often fossilize in intricate, lace-like or branching patterns. Collectors look for these specimens in marine sedimentary rocks, where they are commonly preserved as calcium carbonate structures or sometimes replaced by silica.
Is this bryozoan?
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 bryozoan with a known reference. Bryozoan sits at Mohs 3-5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Bryozoan leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Bryozoan typically shows a dull to earthy luster.
- 4Match the color rangeCompare against the expected color range: white, gray, tan, brown, cream.
- 5Look at form & habitTypical habit: colonial structures, branching, fan-shaped, or encrusting masses.
Often confused with
Bryozoan vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside bryozoan
Minerals reported to co-occur with bryozoan. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Mohs hardness
- 3-5
- Density
- 2.6-2.9 g/cm³
- Streak
- White
- Luster
- Dull to Earthy
- Transparency
- Opaque
- Crystal habit
- Colonial Structures, Branching, Fan-shaped, Or Encrusting Masses
- Cleavage
- None
- Rarity
- Common
- Uses
- Collector, Decorative
- Host rock
- Sedimentary Rocks Like Limestone, Shale, And Siltstone
- Typical price
- $5-50 for small specimens, $100+ for large display slabs
Where rockhounds find bryozoan
1 mapped spotsClassic worldwide localities
- United States
- United Kingdom
- Germany
- China
- Australia
Field-hunting tip
Look in sedimentary rocks like limestone, shale, and siltstone country, the host setting where bryozoan typically forms. If you start seeing calcite, dolomite, quartz in float, you are in the right ground. Field specimens usually show a colonial structures, branching, fan-shaped, or encrusting masses habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Michigan. Start trip planning there.
Common questions
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Find bryozoan on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
