Caseyite is a rare secondary mineral found in oxidized vanadium-uranium deposits. It typically occurs as small, delicate, yellow platy crystals or thin crusts in sandstone cavities.

Hardness

Mohs

Luster

Pearly

Streak

Yellow

Transparency

Translucent

mineralrare

Caseyite

Caseyite is a rare secondary mineral found in oxidized vanadium-uranium deposits. It typically occurs as small, delicate, yellow platy crystals or thin crusts in sandstone cavities.

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

Is this caseyite?

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 caseyite with a known reference. Caseyite 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. Caseyite leaves a yellow streak.
3
Read the luster
Hold the specimen under a strong light. Caseyite typically shows a pearly luster.
4
Match the color range
Compare against the expected color range: yellow, brownish-yellow.
5
Look at form & habit
Crystal system: triclinic. Typical habit: platy crystals, crusts.

Often confused with

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

mineral

Hewettite

Mohs approx 1

How to tell apart: Caseyite is noticeably harder (Mohs 2 vs. approx 1); streak differs, so Caseyite leaves yellow, Hewettite leaves brownish red.

How to tell apart: Streak differs, so Caseyite leaves yellow, Metahewettite leaves deep red; luster reads pearly on Caseyite and subadamantine on Metahewettite.

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Often found alongside caseyite

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

All properties

Chemical formula: K₄(Al₄(OH)₈)(V₁₀O₂₈)·14H₂O
Mohs hardness: 2
Density: 2.47 g/cm³
Colors: Yellow Brownish-yellow
Streak: Yellow
Luster: Pearly
Transparency: Translucent
Crystal system: Triclinic
Crystal habit: Platy Crystals, Crusts
Cleavage: Perfect
Rarity: Rare
Uses: Collector
Host rock: Sandstone Cavities
Typical price: $50-300 per specimen

Where rockhounds find caseyite

Classic worldwide localities

Temple Mountain, Emery County, Utah, USA

Field-hunting tip

Look in sandstone cavities country, the host setting where caseyite typically forms. If you start seeing gypsum, hummerite, hewettite in float, you are in the right ground. Field specimens usually show a platy crystals, crusts habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify caseyite?+

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

Where is caseyite found?+

Notable localities include Temple Mountain, Emery County, Utah, USA.

How much is caseyite worth?+

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

Is caseyite safe to handle?+

It contains toxic constituents. Contains vanadium, which can be toxic if ingested or inhaled as dust. Handle with care and wash hands thoroughly after handling. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like caseyite?+

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

What minerals are found with caseyite?+

Caseyite commonly co-occurs with Gypsum, Hummerite, Hewettite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does caseyite form in?+

Caseyite typically forms in sandstone cavities. Working float back to the host body is the standard way to chase a fresh occurrence.

What is caseyite used for?+

Caseyite is used in collector.

Find caseyite on the map

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