Soddyite is a striking secondary uranium mineral characterized by its bright yellow to yellow-orange crystal clusters. It is typically found in the oxidized zones of uranium deposits and is highly prized by collectors for its vibrant fluorescence under ultraviolet light.

Hardness

3.5

Mohs

Luster

Vitreous

Streak

Yellow

Transparency

Translucent

mineralrare

Soddyite

Hardness: 3.5
Luster: Vitreous
Streak: Yellow
Transparency: Translucent

Is this soddyite?

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 soddyite with a known reference. Soddyite sits at Mohs 3.5, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Soddyite leaves a yellow streak.
3
Read the luster
Hold the specimen under a strong light. Soddyite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: yellow, yellow-orange, brownish-yellow.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: dipyramidal crystals, granular, massive.

Often confused with

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

mineral

Kasolite

Mohs 4-5

How to tell apart: Luster reads vitreous on Soddyite and greasy on Kasolite.

How to tell apart: Soddyite is noticeably harder (Mohs 3.5 vs. 2.5); streak differs, so Soddyite leaves yellow, Uranophane leaves pale yellow.

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Often found alongside soddyite

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

All properties

Chemical formula: (UO₂)₂SiO₄·2H₂O
Mohs hardness: 3.5
Density: 4.7-4.8 g/cm³
Colors: Yellow Yellow-orange Brownish-yellow
Streak: Yellow
Luster: Vitreous
Transparency: Translucent
Crystal system: Orthorhombic
Crystal habit: Dipyramidal Crystals, Granular, Massive
Cleavage: Distinct
Fluorescence: Strong Yellow-green Under SW UV
Rarity: Rare
Uses: Collector
Host rock: Oxidized Zones of Uranium Deposits
Typical price: $50-500 depending on specimen size and quality

Where rockhounds find soddyite

Classic worldwide localities

Shinkolobwe, Democratic Republic of the Congo
Musonoi Mine, Democratic Republic of the Congo
Arvee Prospect, Australia

Field-hunting tip

Look in oxidized zones of uranium deposits country, the host setting where soddyite typically forms. If you start seeing curite, vandenbrandeite, becquerelite in float, you are in the right ground. Field specimens usually show a dipyramidal crystals, granular, massive habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify soddyite?+

Mohs hardness is 3.5. It typically shows a vitreous luster. The streak is yellow. Common colors include yellow, yellow-orange, brownish-yellow.

Where is soddyite found?+

Notable localities include Shinkolobwe, Democratic Republic of the Congo; Musonoi Mine, Democratic Republic of the Congo; Arvee Prospect, Australia.

How much is soddyite worth?+

Typical asking prices fall in the range of $50-500 depending on specimen size and quality. Quality, size, and provenance can move individual specimens well outside that range.

Is soddyite safe to handle?+

This mineral is radioactive. It contains toxic constituents. Radioactive material; emits ionizing radiation. Wash hands thoroughly after handling, store in a sealed container away from living areas, and avoid inhaling dust. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like soddyite?+

Soddyite is most often confused with Kasolite, Uranophane. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with soddyite?+

Soddyite commonly co-occurs with Curite, Vandenbrandeite, Becquerelite, Kasolite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does soddyite form in?+

Soddyite typically forms in oxidized zones of uranium deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is soddyite used for?+

Soddyite is used in collector.

Find soddyite on the map

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