Blastoids are an extinct group of stalked echinoderms known for their distinct bud-like shape, often featuring five-fold radial symmetry similar to a flower bud. Collectors typically look for the 'calyx,' the main body portion, which is commonly found in Paleozoic-aged limestone deposits. They are frequently found in marine sedimentary rocks and are highly prized by amateur paleontologists for their aesthetic beauty and precise symmetry.
Is this blastoid?
2-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Match the color rangeCompare against the expected color range: gray, brown, white, tan.
- 2Look at form & habitTypical habit: pentameral symmetry.
Often confused with
Blastoid vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside blastoid
Minerals reported to co-occur with blastoid. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Crystal habit
- Pentameral Symmetry
- Rarity
- Common
- Uses
- Collector, Decorative
- Host rock
- Limestone
- Typical price
- $5-50 depending on preservation quality
Where rockhounds find blastoid
Classic worldwide localities
- Kentucky
- Indiana
- Illinois
- Tennessee
- United Kingdom
Field-hunting tip
Look in limestone country — that is the host setting where blastoid typically forms. If you start seeing calcite, quartz, pyrite in float, you are in the right ground. Field specimens usually show a pentameral symmetry habit, so train your eye for that shape before scanning the outcrop.
Common questions
Where is blastoid found?+
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Find blastoid on the map
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