Agrinierite is a rare, vibrant orange uranyl oxide mineral that typically forms as a secondary mineral in the oxidized zones of uranium deposits. Collectors should look for its distinctive platy, orange crystals that often occur as thin crusts on uranium-bearing host rocks.

Hardness

Mohs

Luster

Vitreous

Streak

Yellow

Transparency

Translucent

mineralrare

Agrinierite

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

Is this agrinierite?

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

Often confused with

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

mineral

Becquerelite

Mohs 2.5

How to tell apart: Luster reads vitreous on Agrinierite and adamantine on Becquerelite.

Often found alongside agrinierite

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

Uraninite
mineral · Mohs 5-6

All properties

Chemical formula: (K₂,Ca,Sr)U₄O₁₃·6H₂O
Mohs hardness: 3
Density: 5.68 g/cm³
Colors: Orange Yellow-orange
Streak: Yellow
Luster: Vitreous
Transparency: Translucent
Crystal system: Orthorhombic
Crystal habit: Platy Crystals, Crusts
Cleavage: Perfect
Rarity: Rare
Uses: Collector
Host rock: Hydrothermal Uranium Deposits
Typical price: $100-500 per specimen

Where rockhounds find agrinierite

Classic worldwide localities

Margnac mine, France
Klodawa, Poland

Field-hunting tip

Look in hydrothermal uranium deposits country — that is the host setting where agrinierite typically forms. If you start seeing uranyl carbonates, gummite, uraninite 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 agrinierite?+

Mohs hardness is 3. It typically shows a vitreous luster. The streak is yellow. Common colors include orange, yellow-orange.

Where is agrinierite found?+

Notable localities include Margnac mine, France; Klodawa, Poland.

How much is agrinierite worth?+

Typical asking prices fall in the range of $100-500 per specimen. Quality, size, and provenance can move individual specimens well outside that range.

Is agrinierite safe to handle?+

This mineral is radioactive. It contains toxic constituents. Contains uranium and is significantly radioactive; handle with gloves and store in a lead-lined container. Do not inhale dust or allow skin contact. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like agrinierite?+

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

What minerals are found with agrinierite?+

Agrinierite commonly co-occurs with Uranyl carbonates, Gummite, Uraninite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does agrinierite form in?+

Agrinierite typically forms in hydrothermal uranium deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is agrinierite used for?+

Agrinierite is used in collector.

Find agrinierite on the map

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