Tyuyamunite is a secondary uranium vanadate mineral that typically forms as bright yellow earthy crusts or thin platy crystal aggregates. It is frequently found in sandstone-hosted uranium deposits within the Colorado Plateau and is highly valued by mineral collectors for its intense fluorescence under short-wave UV.

Hardness

Mohs

Luster

Pearly

Streak

Yellow

Transparency

Translucent

mineraluncommonTyuyamunite Group family

Tyuyamunite

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

Is this tyuyamunite?

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

Often confused with

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

mineral

Carnotite

Mohs 2

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

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

Often found alongside tyuyamunite

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

All properties

Chemical formula: Ca(UO₂)₂(VO₄)₂·5-8H₂O
Mohs hardness: 2
Density: 3.7-4.4 g/cm³
Colors: Yellow Canary Yellow Greenish-yellow
Streak: Yellow
Luster: Pearly
Transparency: Translucent
Crystal system: Orthorhombic
Crystal habit: Platy Crystals, Scales, Or Crusts
Cleavage: Perfect On {001}
Fluorescence: Bright Yellow-green Under UV Light
Rarity: Uncommon
Uses: Collector, Uranium Ore
Host rock: Sedimentary Sandstone Deposits
Typical price: $15-80 per specimen

Where rockhounds find tyuyamunite

Classic worldwide localities

Tyuya-Muyun District, Kyrgyzstan
Colorado Plateau, USA
Utah, USA
Katanga Province, DR Congo

Field-hunting tip

Look in sedimentary sandstone deposits country, the host setting where tyuyamunite typically forms. If you start seeing carnotite, vanadinite, malachite in float, you are in the right ground. Field specimens usually show a platy crystals, scales, or crusts habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify tyuyamunite?+

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

Where is tyuyamunite found?+

Notable localities include Tyuya-Muyun District, Kyrgyzstan; Colorado Plateau, USA; Utah, USA; Katanga Province, DR Congo.

How much is tyuyamunite worth?+

Typical asking prices fall in the range of $15-80 per specimen. Quality, size, and provenance can move individual specimens well outside that range.

Is tyuyamunite safe to handle?+

This mineral is radioactive. It contains toxic constituents. This mineral is radioactive and contains heavy metals. Always store in a labeled, lead-lined, or airtight container away from living areas and wash hands thoroughly after handling. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like tyuyamunite?+

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

What minerals are found with tyuyamunite?+

Tyuyamunite commonly co-occurs with Carnotite, Vanadinite, Malachite, Calcite, Gypsum. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does tyuyamunite form in?+

Tyuyamunite typically forms in sedimentary sandstone deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is tyuyamunite used for?+

Tyuyamunite is used in collector, uranium ore.

Find tyuyamunite on the map

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