RockHoundR

Torbernite is a highly sought-after secondary uranium mineral known for its vibrant emerald-green, thin tabular or micaceous crystal clusters. It is an oxidation product of primary uranium minerals and is most commonly found in the weathered zones of uranium-bearing hydrothermal deposits.

Hardness
2-2.5
Mohs
Luster
Vitreous, subadamantine, waxy, pearly on cleavages; becoming dull on dehydration to metatorbernite
Streak
Pale green
Transparency
Transparent to translucent

Is this torbernite?

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 torbernite with a known reference. Torbernite 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. Streak: pale green.
  • 3
    Read the luster
    Hold the specimen under a strong light. Luster: vitreous, subadamantine, waxy, pearly on cleavages; becoming dull on dehydration to metatorbernite.
  • 4
    Match the color range
    Compare against the expected color range: emerald green, grass green, leek green, green, apple green, siskin green.
  • 5
    Look at form & habit
    Crystal system: tetragonal. Typical habit: earthy, foliated, tabular.

Often confused with

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

Autunite mineral
mineral
Autunite
Mohs 2-2.5
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No image
mineral
Metanatroautunite
Mohs 2-2.5

How to tell apart: Streak differs, so Torbernite leaves pale green, Metanatroautunite leaves yellow.

Compare →

Often found alongside torbernite

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

All properties

Chemical formula
Cu(UO₂)₂(PO₄)₂·10-12H₂O
Mohs hardness
2-2.5
Density
3.22 g/cm³
Colors
Emerald greenGrass greenLeek greenGreenApple greenSiskin green
Streak
Pale green
Luster
Vitreous, subadamantine, waxy, pearly on cleavages; becoming dull on dehydration to metatorbernite
Transparency
Transparent to translucent
Crystal system
Tetragonal
Crystal habit
Earthy, foliated, tabular
Cleavage
Perfect on {001}, micaceous; indistinct on {100}
Rarity
Uncommon
Uses
Collector
Host rock
An uncommon secondary mineral formed in the oxidized zone of some uraniferous copper deposits

Where rockhounds find torbernite

3 mapped spots

Classic worldwide localities

  • Chalk Mountain, near Spruce Pine, Mitchell Co., North Carolina, USA
  • Majuba Hill mine, Antelope district, Pershing Co., Nevada, USA
  • Jáchymov (Joachimsthal), Czech Republic
  • Schneeberg, Johanngeorgenstadt, Saxony, Germany
  • Margabal, Aveyron, and at Les Bois Noirs, Puy-de-Dôme, France
  • A number of mines in Cornwall, as Wheal Basset, Stenna Gwyn, England

Field-hunting tip

Where it forms: An uncommon secondary mineral formed in the oxidized zone of some uraniferous copper deposits. If you start seeing metatorbernite, autunite, zeunerite in float, you are in the right ground. Typical habit: earthy, foliated, tabular. Train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Utah, Connecticut. Start trip planning there.

Browse 3 U.S. spots for torbernite →

Common questions

How do you identify torbernite?+
Mohs hardness is 2-2.5. Luster: vitreous, subadamantine, waxy, pearly on cleavages; becoming dull on dehydration to metatorbernite. The streak is pale green. Common colors include emerald green, grass green, leek green, green.
Where is torbernite found?+
Notable localities include Chalk Mountain, near Spruce Pine, Mitchell Co., North Carolina, USA; Majuba Hill mine, Antelope district, Pershing Co., Nevada, USA; Jáchymov (Joachimsthal), Czech Republic; Schneeberg, Johanngeorgenstadt, Saxony, Germany; Margabal, Aveyron, and at Les Bois Noirs, Puy-de-Dôme, France.
Can I find torbernite in the United States?+
RockHoundR maps 3 torbernite rockhounding spots across 2 U.S. states. The top states are Utah, Connecticut.
Is torbernite safe to handle?+
Torbernite contains copper and uranium or thorium and calls for real care. Torbernite is highly radioactive and contains uranium; handle with gloves, wash hands thoroughly after contact, and store in a lead-lined or secure container away from living areas. Avoid creating dust or inhaling particles.
What rocks look like torbernite?+
Torbernite is most often confused with Autunite, Metanatroautunite. A quick hardness test and a streak check separate the look-alikes faster than color alone.
What minerals are found with torbernite?+
Torbernite commonly co-occurs with Metatorbernite, Autunite, Zeunerite, Uraninite. Spotting any of these in float or country rock is a useful trip signal.
What kind of rock does torbernite form in?+
Where it forms: An uncommon secondary mineral formed in the oxidized zone of some uraniferous copper deposits. Working float back to the host body is the standard way to chase a fresh occurrence.
What is torbernite used for?+
Torbernite is used in collector.

Find torbernite on the map

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

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