Cuprosklodowskite is a striking secondary uranium mineral that forms beautiful, bright green acicular or fibrous needle-like crystals. It is highly sought after by collectors for its vivid color and intense green fluorescence under UV light, though it requires specialized storage due to its radioactivity and fragility.

Hardness
3-4
Mohs
Luster
Vitreous
Streak
Pale Green
Transparency
Translucent

Is this cuprosklodowskite?

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 cuprosklodowskite with a known reference. Cuprosklodowskite sits at Mohs 3-4 — softer than the next harder reference, harder than the previous one.
  • 2
    Check the streak
    Drag the specimen across an unglazed porcelain plate. Cuprosklodowskite leaves a pale green streak.
  • 3
    Read the luster
    Hold the specimen under a strong light. Cuprosklodowskite typically shows a vitreous luster.
  • 4
    Match the color range
    Compare against the expected color range: grass-green, emerald-green, yellow-green.
  • 5
    Look at form & habit
    Crystal system: triclinic. Typical habit: acicular or fibrous radial aggregates, crusts.

Often confused with

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

Often found alongside cuprosklodowskite

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

All properties

Chemical formula
Cu(UO₂)₂(SiO₃OH)₂·6H₂O
Mohs hardness
3-4
Density
3.5 g/cm³
Streak
Pale Green
Luster
Vitreous
Transparency
Translucent
Crystal system
Triclinic
Crystal habit
Acicular or Fibrous Radial Aggregates, Crusts
Cleavage
Perfect in One Direction
Fluorescence
Bright Green Under SW and LW UV
Rarity
Rare
Uses
Collector
Host rock
Oxidized Zones of Uranium-bearing Hydrothermal Deposits
Typical price
$20-200 for micro-mounts to small cabinet specimens

Where rockhounds find cuprosklodowskite

Classic worldwide localities

  • Musonoi Mine, Democratic Republic of the Congo
  • Shinkolobwe, Democratic Republic of the Congo
  • Joachimsthal, Czech Republic

Field-hunting tip

Look in oxidized zones of uranium-bearing hydrothermal deposits country — that is the host setting where cuprosklodowskite typically forms. If you start seeing sklodowskite, kasolite, becquerelite in float, you are in the right ground. Field specimens usually show a acicular or fibrous radial aggregates, crusts habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify cuprosklodowskite?+
Mohs hardness is 3-4. It typically shows a vitreous luster. The streak is pale green. Common colors include grass-green, emerald-green, yellow-green.
Where is cuprosklodowskite found?+
Notable localities include Musonoi Mine, Democratic Republic of the Congo; Shinkolobwe, Democratic Republic of the Congo; Joachimsthal, Czech Republic.
How much is cuprosklodowskite worth?+
Typical asking prices fall in the range of $20-200 for micro-mounts to small cabinet specimens. Quality, size, and provenance can move individual specimens well outside that range.
Is cuprosklodowskite safe to handle?+
This mineral is radioactive. It contains toxic constituents. This mineral is radioactive and contains copper and uranium; handle with gloves, avoid inhalation of dust, and store in a sealed lead-lined container away from living areas. Handle with care, avoid grinding or breathing dust, and store separately.
What rocks look like cuprosklodowskite?+
Cuprosklodowskite is most often confused with Vandenbrandeite, Torbernite, Autunite. A quick hardness test and a streak check separate the look-alikes faster than color alone.
What minerals are found with cuprosklodowskite?+
Cuprosklodowskite commonly co-occurs with Sklodowskite, Kasolite, Becquerelite, Studtite. Spotting any of these in float or country rock is a useful trip signal.
What kind of rock does cuprosklodowskite form in?+
Cuprosklodowskite typically forms in oxidized zones of uranium-bearing hydrothermal deposits. Working float back to the host body is the standard way to chase a fresh occurrence.
What is cuprosklodowskite used for?+
Cuprosklodowskite is used in collector.

Find cuprosklodowskite on the map

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

Download on the App StoreGet it on Google Play