Sengierite is a rare copper uranyl vanadate that typically forms as thin, vibrant yellow platy crystals or earthy coatings. Collectors prize it for its bright color, though it is primarily sought after by advanced mineral enthusiasts due to its radioactive nature and specialized occurrence.

Hardness

2-3

Mohs

Luster

Pearly

Streak

Yellow

Transparency

Translucent

mineralrare

Sengierite

Hardness: 2-3
Luster: Pearly
Streak: Yellow
Transparency: Translucent

Is this sengierite?

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

Often confused with

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

How to tell apart: Luster reads pearly on Sengierite and dull on Carnotite.

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Often found alongside sengierite

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

All properties

Chemical formula: Cu₂(UO₂)₂(VO₄)₂·8-10H₂O
Mohs hardness: 2-3
Density: 4.3 g/cm³
Colors: Yellow Greenish-yellow
Streak: Yellow
Luster: Pearly
Transparency: Translucent
Crystal system: Orthorhombic
Crystal habit: Platy Crystals, Crusts, Or Radiating Aggregates
Cleavage: Perfect in One Direction
Rarity: Rare
Uses: Collector
Host rock: Oxidized Zones of Uranium-vanadium Deposits
Typical price: $50-300 depending on specimen size and quality

Where rockhounds find sengierite

Classic worldwide localities

Musonoi Mine, Democratic Republic of the Congo
Shinkolobwe, Democratic Republic of the Congo
Colorado Plateau, USA
Utah, USA

Field-hunting tip

Look in oxidized zones of uranium-vanadium deposits country — that is the host setting where sengierite typically forms. If you start seeing curite, vandenbrandeite, metatorbernite in float, you are in the right ground. Field specimens usually show a platy crystals, crusts, or radiating aggregates habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify sengierite?+

Mohs hardness is 2-3. It typically shows a pearly luster. The streak is yellow. Common colors include yellow, greenish-yellow.

Where is sengierite found?+

Notable localities include Musonoi Mine, Democratic Republic of the Congo; Shinkolobwe, Democratic Republic of the Congo; Colorado Plateau, USA; Utah, USA.

How much is sengierite worth?+

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

Is sengierite safe to handle?+

This mineral is radioactive. It contains toxic constituents. This mineral is both radioactive and contains copper/vanadium; handle with caution using gloves and wash hands thoroughly. Store in a lead-lined container away from other mineral specimens. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like sengierite?+

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

What minerals are found with sengierite?+

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

What kind of rock does sengierite form in?+

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

What is sengierite used for?+

Sengierite is used in collector.

Find sengierite on the map

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