Kahlerite is a rare secondary uranium phosphate-arsenate mineral belonging to the autunite group. It typically appears as bright yellow to yellow-green platy crystals that resemble autunite but are distinguished by their chemical composition and association with arsenic-rich environments.

Hardness

2-2.5

Mohs

Luster

Pearly

Streak

Yellow

Transparency

Transparent

mineralrareAutunite Group family

Kahlerite

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

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Is this kahlerite?

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 kahlerite with a known reference. Kahlerite 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. Kahlerite leaves a yellow streak.
3
Read the luster
Hold the specimen under a strong light. Kahlerite 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: tabular crystals, micaceous aggregates.

Often confused with

Kahlerite 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 — Kahlerite leaves yellow, Autunite leaves pale yellow.

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

Often found alongside kahlerite

Minerals reported to co-occur with kahlerite. 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)₂·12H₂O
Mohs hardness: 2-2.5
Density: 3.2 g/cm³
Colors: Yellow Yellow-green
Streak: Yellow
Luster: Pearly
Transparency: Transparent
Crystal system: Tetragonal
Crystal habit: Tabular Crystals, Micaceous Aggregates
Cleavage: Perfect Basal
Fluorescence: Bright Yellow-green Under UV
Rarity: Rare
Uses: Collector, Reference Specimen
Host rock: Uranium-bearing Hydrothermal Veins
Typical price: $20-150 per specimen depending on size and quality

Where rockhounds find kahlerite

Classic worldwide localities

Schneeberg, Germany
Jachymov, Czech Republic
Cornwall, England

Field-hunting tip

Look in uranium-bearing hydrothermal veins country — that is the host setting where kahlerite typically forms. If you start seeing uraninite, arsenopyrite, 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 kahlerite?+

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

Where is kahlerite found?+

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

How much is kahlerite worth?+

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

Is kahlerite safe to handle?+

This mineral is radioactive. It contains toxic constituents. Kahlerite contains uranium and arsenic; it is radioactive and toxic if ingested or inhaled as dust. Always wash hands after handling, avoid creating 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 kahlerite?+

Kahlerite 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 kahlerite?+

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

What kind of rock does kahlerite form in?+

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

What is kahlerite used for?+

Kahlerite is used in collector, reference specimen.

Find kahlerite on the map

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