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.

fossilcommon

Blastoid

Is this blastoid?

2-step field check

Run through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.

1
Match the color range
Compare against the expected color range: gray, brown, white, tan.
2
Look at form & habit
Typical 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

Colors: Gray Brown White Tan
Crystal habit: Pentameral Symmetry
Rarity: Common
Uses: Collector, Decorative
Host rock: Limestone
Typical price: $5-50 depending on preservation quality

Where rockhounds find blastoid

1 mapped spots

Classic worldwide localities

Kentucky
Indiana
Illinois
Tennessee
United Kingdom

Field-hunting tip

Look in limestone country, 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. In the U.S., the densest reported localities are in Michigan. Start trip planning there.

Browse 1 U.S. spots for blastoid →

Common questions

Where is blastoid found?+

Notable localities include Kentucky; Indiana; Illinois; Tennessee; United Kingdom.

Can I find blastoid in the United States?+

RockHoundR maps 1 blastoid rockhounding spots across 1 U.S. states. The top states are Michigan.

How much is blastoid worth?+

Typical asking prices fall in the range of $5-50 depending on preservation quality. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like blastoid?+

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

What minerals are found with blastoid?+

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

What kind of rock does blastoid form in?+

Blastoid typically forms in limestone. Working float back to the host body is the standard way to chase a fresh occurrence.

What is blastoid used for?+

Blastoid is used in collector, decorative.

Find blastoid on the map

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