Markcooperite is an extremely rare lead-uranium silicate mineral discovered in the Musonoi Mine. It typically forms small, yellow, translucent tabular crystals often found associated with other uranium-bearing secondary minerals in oxidation zones.

Hardness

3-4

Mohs

Luster

Adamantine

Streak

Yellow

Transparency

Translucent

mineralrare

Markcooperite

Hardness: 3-4
Luster: Adamantine
Streak: Yellow
Transparency: Translucent

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Is this markcooperite?

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 markcooperite with a known reference. Markcooperite 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. Markcooperite leaves a yellow streak.
3
Read the luster
Hold the specimen under a strong light. Markcooperite typically shows a adamantine luster.
4
Match the color range
Compare against the expected color range: yellow, yellow-brown.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: tabular crystals, aggregates.

Often confused with

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

mineral

Kasolite

Mohs 4-5

How to tell apart: Luster reads adamantine on Markcooperite and greasy on Kasolite.

How to tell apart: Streak differs, so Markcooperite leaves yellow, Curite leaves orange.

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Often found alongside markcooperite

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

All properties

Chemical formula: Pb₂SiUO₈
Mohs hardness: 3-4
Density: 8.8-9.0 g/cm³
Colors: Yellow Yellow-brown
Streak: Yellow
Luster: Adamantine
Transparency: Translucent
Crystal system: Orthorhombic
Crystal habit: Tabular Crystals, Aggregates
Cleavage: None Observed
Rarity: Rare
Uses: Collector
Host rock: Oxidized Zones of Uranium Deposits
Typical price: $200-1000+ for rare micro specimens

Where rockhounds find markcooperite

Classic worldwide localities

Musonoi Mine, Democratic Republic of the Congo

Field-hunting tip

Look in oxidized zones of uranium deposits country, the host setting where markcooperite typically forms. If you start seeing soddyite, kasolite, curite in float, you are in the right ground. Field specimens usually show a tabular crystals, aggregates habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify markcooperite?+

Mohs hardness is 3-4. It typically shows a adamantine luster. The streak is yellow. Common colors include yellow, yellow-brown.

Where is markcooperite found?+

Notable localities include Musonoi Mine, Democratic Republic of the Congo.

How much is markcooperite worth?+

Typical asking prices fall in the range of $200-1000+ for rare micro specimens. Quality, size, and provenance can move individual specimens well outside that range.

Is markcooperite safe to handle?+

This mineral is radioactive. It contains toxic constituents. Contains uranium and lead; handle with care, store in a lead-lined container, and wash hands thoroughly after handling. Do not ingest dust. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like markcooperite?+

Markcooperite is most often confused with Kasolite, Curite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with markcooperite?+

Markcooperite commonly co-occurs with soddyite, kasolite, curite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does markcooperite form in?+

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

What is markcooperite used for?+

Markcooperite is used in collector.

Find markcooperite on the map

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