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 — 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 — that is 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.