Turritella Agate is a silicified sedimentary rock containing abundant fossils of the marine gastropod Elimia tenera. It is highly valued by lapidaries for the striking, high-contrast patterns created by the darker shell spirals set against a lighter, translucent-to-opaque chalcedony matrix.

Hardness

6.5-7

Mohs

Luster

Waxy

Transparency

Opaque

fossilcommonChalcedony family

Turritella Agate

Also: Turritella Stone

Hardness: 6.5-7
Luster: Waxy
Transparency: Opaque

Is this turritella agate?

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 turritella agate with a known reference. Turritella Agate sits at Mohs 6.5-7, softer than the next harder reference, harder than the previous one.
2
Name the organism
Decide what left the fossil before worrying about the rock. Organism: Freshwater snail Elimia tenera (named after the unrelated sea snail Turritella). Age: Eocene (46 to 51 million years ago), Laney Member of the Green River Formation.
3
Check the preservation
Preservation: Silicified shells. That controls the weight, the hardness and how the piece takes a polish.
4
Read the luster
Hold the specimen under a strong light. Luster: waxy.
5
Match the color range
Compare against the expected color range: brown, tan, gray, cream.

Often confused with

Turritella Agate vs. its common look-alikes, and how to tell them apart in the field.

How to tell apart: Luster reads waxy on Turritella Agate and vitreous to waxy on Petrified Wood.

Compare →

Often found alongside turritella agate

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

All properties

Mohs hardness: 6.5-7
Density: 2.55-2.70 g/cm³
Colors: Brown Tan Gray Cream
Luster: Waxy
Transparency: Opaque
Rarity: Common
Uses: Lapidary, Decorative, Collector
Host rock: sedimentary rock
Organism: Freshwater snail Elimia tenera (named after the unrelated sea snail Turritella)
Age: Eocene (46 to 51 million years ago), Laney Member of the Green River Formation
Preservation: Silicified shells

Where rockhounds find turritella agate

7 mapped spots

Classic worldwide localities

Green River Formation, Wyoming, USA

Field-hunting tip

Where it forms: sedimentary rock. If you start seeing quartz, calcite in float, you are in the right ground. In the U.S., the densest reported localities are in Wyoming, Texas. Start trip planning there.

Browse 7 U.S. spots for turritella agate →

More turritella agate photos

Common questions

How do you identify turritella agate?+

Mohs hardness is 6.5-7. Organism: Freshwater snail Elimia tenera (named after the unrelated sea snail Turritella). Preservation: Silicified shells. Luster: waxy. Common colors include brown, tan, gray, cream.

Where is turritella agate found?+

Notable localities include Green River Formation, Wyoming, USA.

Can I find turritella agate in the United States?+

RockHoundR maps 7 turritella agate rockhounding spots across 2 U.S. states. The top states are Wyoming, Texas.

What rocks look like turritella agate?+

Turritella Agate is most often confused with Chert, Jasper, Petrified Wood. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with turritella agate?+

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

What kind of rock does turritella agate form in?+

Where it forms: sedimentary rock. Working float back to the host body is the standard way to chase a fresh occurrence.

What is turritella agate used for?+

Turritella Agate is used in lapidary, decorative, collector.

Find turritella agate on the map

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