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, 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.