Schmitterite is an extremely rare uranium tellurite mineral typically found as a secondary oxidation product. It usually appears as fine-grained, pale yellow crusts or tiny, delicate platy crystals, often associated with other rare tellurium minerals in uranium-rich localities.

Hardness

Mohs

Luster

Pearly

Streak

Yellow

Transparency

Translucent

mineralrare

Schmitterite

Hardness: 3
Luster: Pearly
Streak: Yellow
Transparency: Translucent

Is this schmitterite?

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 schmitterite with a known reference. Schmitterite sits at Mohs 3, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Schmitterite leaves a yellow streak.
3
Read the luster
Hold the specimen under a strong light. Schmitterite typically shows a pearly luster.
4
Match the color range
Compare against the expected color range: yellow, pale yellow.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: platy crystals, crusts, pulverulent aggregates.

Often confused with

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

mineral

Carnotite

Mohs 2

How to tell apart: Schmitterite is noticeably harder (Mohs 3 vs. 2); luster reads pearly on Schmitterite and dull on Carnotite.

How to tell apart: Streak differs, so Schmitterite leaves yellow, Autunite leaves pale yellow.

Compare →

Often found alongside schmitterite

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

All properties

Chemical formula: UO₂TeO₃
Mohs hardness: 3
Density: 6.05 g/cm³
Colors: Yellow Pale Yellow
Streak: Yellow
Luster: Pearly
Transparency: Translucent
Crystal system: Orthorhombic
Crystal habit: Platy Crystals, Crusts, Pulverulent Aggregates
Cleavage: Perfect
Rarity: Rare
Uses: Collector
Host rock: Oxidized Zones of Uranium-tellurium Bearing Hydrothermal Deposits
Typical price: $50-300 per thumbnail specimen

Where rockhounds find schmitterite

Classic worldwide localities

Moab, Utah, USA
Marysvale, Utah, USA
Gunnison County, Colorado, USA

Field-hunting tip

Look in oxidized zones of uranium-tellurium bearing hydrothermal deposits country, the host setting where schmitterite typically forms. If you start seeing uraninite, tellurium, pyrite in float, you are in the right ground. Field specimens usually show a platy crystals, crusts, pulverulent aggregates habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify schmitterite?+

Mohs hardness is 3. It typically shows a pearly luster. The streak is yellow. Common colors include yellow, pale yellow.

Where is schmitterite found?+

Notable localities include Moab, Utah, USA; Marysvale, Utah, USA; Gunnison County, Colorado, USA.

How much is schmitterite worth?+

Typical asking prices fall in the range of $50-300 per thumbnail specimen. Quality, size, and provenance can move individual specimens well outside that range.

Is schmitterite safe to handle?+

This mineral is radioactive. It contains toxic constituents. Contains uranium and tellurium; handle with care. Radioactive mineral requires secure storage away from other specimens and proper containment to prevent ingestion or inhalation of dust. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like schmitterite?+

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

What minerals are found with schmitterite?+

Schmitterite commonly co-occurs with Uraninite, Tellurium, Pyrite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does schmitterite form in?+

Schmitterite typically forms in oxidized zones of uranium-tellurium bearing hydrothermal deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is schmitterite used for?+

Schmitterite is used in collector.

Find schmitterite on the map

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