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 — 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 — that is 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.