Silicified oolite consists of spherical grains called ooids that have been replaced or cemented by microcrystalline silica. Collectors look for the distinct 'fish-egg' texture visible in cross-sections, which polishes beautifully for lapidary work.

Hardness

6.5-7

Mohs

Luster

Waxy

Streak

White

Transparency

Translucent

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Silicified Oolite

Hardness: 6.5-7
Luster: Waxy
Streak: White
Transparency: Translucent

No image

Is this silicified oolite?

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 silicified oolite with a known reference. Silicified Oolite sits at Mohs 6.5-7 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Silicified Oolite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Silicified Oolite typically shows a waxy luster.
4
Match the color range
Compare against the expected color range: white, gray, brown, tan, red.
5
Look at form & habit
Typical habit: oolitic.

Often confused with

Silicified Oolite vs. its common look-alikes — and how to tell them apart in the field.

sedimentary

Oolitic Limestone

Mohs 3

How to tell apart: Silicified Oolite is noticeably harder (Mohs 6.5-7 vs. 3); luster reads waxy on Silicified Oolite and dull on Oolitic Limestone.

Often found alongside silicified oolite

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

All properties

Chemical formula: SiO₂
Mohs hardness: 6.5-7
Density: 2.6-2.65 g/cm³
Colors: White Gray Brown Tan Red
Streak: White
Luster: Waxy
Transparency: Translucent
Crystal habit: Oolitic
Cleavage: None
Rarity: Common
Uses: Lapidary, Collector, Decorative
Host rock: Sedimentary Basins
Typical price: $5-30 for small cabochons or rough specimens

Where rockhounds find silicified oolite

2 mapped spots

Classic worldwide localities

Pennsylvania, USA
Utah, USA
France
United Kingdom

Field-hunting tip

Look in sedimentary basins country — that is the host setting where silicified oolite typically forms. If you start seeing quartz, calcite, dolomite in float, you are in the right ground. Field specimens usually show a oolitic habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Georgia — start trip planning there.

Browse 2 U.S. spots for silicified oolite →

Common questions

How do you identify silicified oolite?+

Mohs hardness is 6.5-7. It typically shows a waxy luster. The streak is white. Common colors include white, gray, brown, tan.

Where is silicified oolite found?+

Notable localities include Pennsylvania, USA; Utah, USA; France; United Kingdom.

Can I find silicified oolite in the United States?+

RockHoundR maps 2 silicified oolite rockhounding spots across 1 U.S. states — the top states are Georgia.

How much is silicified oolite worth?+

Typical asking prices fall in the range of $5-30 for small cabochons or rough specimens. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like silicified oolite?+

Silicified Oolite is most often confused with Oolitic Limestone, Orbicular Jasper. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with silicified oolite?+

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

What kind of rock does silicified oolite form in?+

Silicified Oolite typically forms in sedimentary basins. Working float back to the host body is the standard way to chase a fresh occurrence.

What is silicified oolite used for?+

Silicified Oolite is used in lapidary, collector, decorative.

Find silicified oolite on the map

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