Metakahlerite is a rare secondary uranium mineral that forms through the dehydration of primary minerals in oxidized hydrothermal veins. Collectors prize its bright yellow tabular crystals, which are strongly fluorescent under UV light. Due to its radioactive and toxic nature, it should only be handled by experienced mineral collectors with proper safety protocols.

Hardness

2-3

Mohs

Luster

Vitreous

Streak

Yellow

Transparency

Translucent

mineralrareMeta-autunite Group family

Metakahlerite

Hardness: 2-3
Luster: Vitreous
Streak: Yellow
Transparency: Translucent

Is this metakahlerite?

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 metakahlerite with a known reference. Metakahlerite sits at Mohs 2-3 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Metakahlerite leaves a yellow streak.
3
Read the luster
Hold the specimen under a strong light. Metakahlerite typically shows a vitreous 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: tabular crystals, micaceous aggregates.

Often confused with

Metakahlerite 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 — Metakahlerite leaves yellow, Autunite leaves pale yellow; luster reads vitreous on Metakahlerite and pearly on Autunite.

How to tell apart: Luster reads vitreous on Metakahlerite and pearly on Meta-autunite.

How to tell apart: Streak differs — Metakahlerite leaves yellow, Torbernite leaves pale green.

Compare →

Often found alongside metakahlerite

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

All properties

Chemical formula: Fe(UO₂)₂(AsO₄)₂·8H₂O
Mohs hardness: 2-3
Density: 3.32 g/cm³
Colors: Yellow Yellow-green
Streak: Yellow
Luster: Vitreous
Transparency: Translucent
Crystal system: Tetragonal
Crystal habit: Tabular Crystals, Micaceous Aggregates
Cleavage: Perfect Basal
Fluorescence: Bright Green Under UV Light
Rarity: Rare
Uses: Collector
Host rock: Oxidized Zones of Hydrothermal Uranium-arsenic Deposits
Typical price: $50-300 per specimen depending on size and quality

Where rockhounds find metakahlerite

Classic worldwide localities

Schneeberg, Saxony, Germany
Jáchymov, Czech Republic
Cornwall, England

Field-hunting tip

Look in oxidized zones of hydrothermal uranium-arsenic deposits country — that is the host setting where metakahlerite typically forms. If you start seeing uraninite, pharmacosiderite, scorodite in float, you are in the right ground. Field specimens usually show a tabular crystals, micaceous aggregates habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify metakahlerite?+

Mohs hardness is 2-3. It typically shows a vitreous luster. The streak is yellow. Common colors include yellow, yellow-green.

Where is metakahlerite found?+

Notable localities include Schneeberg, Saxony, Germany; Jáchymov, Czech Republic; Cornwall, England.

How much is metakahlerite worth?+

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

Is metakahlerite safe to handle?+

This mineral is radioactive. It contains toxic constituents. This mineral is radioactive and contains uranium and arsenic; handle with care, use gloves, avoid inhaling dust, and store in a lead-lined container away from living areas. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like metakahlerite?+

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

What minerals are found with metakahlerite?+

Metakahlerite commonly co-occurs with Uraninite, Pharmacosiderite, Scorodite, Arsenopyrite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does metakahlerite form in?+

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

What is metakahlerite used for?+

Metakahlerite is used in collector.

Find metakahlerite on the map

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