Metanatroautunite is a rare secondary uranium mineral formed by the dehydration of natroautunite. It typically appears as bright yellow or yellow-green platy crusts and is highly sought after by collectors for its brilliant yellow-green fluorescence under ultraviolet light.

Hardness

2-2.5

Mohs

Luster

Pearly

Streak

Yellow

Transparency

Translucent

mineralrareAutunite Group family

Metanatroautunite

Hardness: 2-2.5
Luster: Pearly
Streak: Yellow
Transparency: Translucent

No image

Is this metanatroautunite?

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 metanatroautunite with a known reference. Metanatroautunite sits at Mohs 2-2.5 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Metanatroautunite leaves a yellow streak.
3
Read the luster
Hold the specimen under a strong light. Metanatroautunite typically shows a pearly luster.
4
Match the color range
Compare against the expected color range: yellow, yellow-green.
5
Look at form & habit
Crystal system: tetragonal. Typical habit: platy crystals, micaceous aggregates, crusts.

Often confused with

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

mineral

Autunite

Mohs 2-2.5

How to tell apart: Streak differs — Metanatroautunite leaves yellow, Autunite leaves pale yellow.

How to tell apart: Streak differs — Metanatroautunite leaves yellow, Torbernite leaves pale green; luster reads pearly on Metanatroautunite and vitreous on Torbernite.

Often found alongside metanatroautunite

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

All properties

Chemical formula: Na₂(UO₂)₂(PO₄)₂·6H₂O
Mohs hardness: 2-2.5
Density: 3.3-3.4 g/cm³
Colors: Yellow Yellow-green
Streak: Yellow
Luster: Pearly
Transparency: Translucent
Crystal system: Tetragonal
Crystal habit: Platy Crystals, Micaceous Aggregates, Crusts
Cleavage: Perfect Basal
Fluorescence: Bright Yellow-green Under UV Light
Rarity: Rare
Uses: Collector
Host rock: Oxidized Zones of Uranium-bearing Hydrothermal Veins
Typical price: $20-150 per specimen depending on size and intensity of fluorescence

Where rockhounds find metanatroautunite

Classic worldwide localities

France
USA
Germany
Portugal
Australia

Field-hunting tip

Look in oxidized zones of uranium-bearing hydrothermal veins country — that is the host setting where metanatroautunite typically forms. If you start seeing uraninite, gummite, chalcedony in float, you are in the right ground. Field specimens usually show a platy crystals, micaceous aggregates, crusts habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify metanatroautunite?+

Mohs hardness is 2-2.5. It typically shows a pearly luster. The streak is yellow. Common colors include yellow, yellow-green.

Where is metanatroautunite found?+

Notable localities include France; USA; Germany; Portugal; Australia.

How much is metanatroautunite worth?+

Typical asking prices fall in the range of $20-150 per specimen depending on size and intensity of fluorescence. Quality, size, and provenance can move individual specimens well outside that range.

Is metanatroautunite safe to handle?+

This mineral is radioactive. It contains toxic constituents. This mineral is radioactive and contains uranium; handle with care using gloves and store in a lead-lined container. Avoid inhaling dust or ingestion; wash hands thoroughly after handling. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like metanatroautunite?+

Metanatroautunite is most often confused with Autunite, Torbernite, Meta-autunite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with metanatroautunite?+

Metanatroautunite commonly co-occurs with Uraninite, Gummite, Chalcedony, Quartz. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does metanatroautunite form in?+

Metanatroautunite typically forms in oxidized zones of uranium-bearing hydrothermal veins. Working float back to the host body is the standard way to chase a fresh occurrence.

What is metanatroautunite used for?+

Metanatroautunite is used in collector.

Find metanatroautunite on the map

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