Mundite is a rare secondary uranium phosphate mineral that typically forms as a crust or small platy crystals. It is almost exclusively found in the weathered zones of granitic pegmatites, specifically documented in the Democratic Republic of the Congo. Collectors should look for its characteristic yellowish, earthy appearance alongside other uranium secondary species.

Hardness

2-3

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrare

Mundite

Hardness: 2-3
Luster: Vitreous
Streak: White
Transparency: Transparent

Is this mundite?

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 mundite with a known reference. Mundite sits at Mohs 2-3, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: white.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous.
4
Match the color range
Compare against the expected color range: golden yellow, light yellow.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: platy crystals, granular aggregates.

Often confused with

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

mineral

Meta-autunite

Mohs 2-2.5

How to tell apart: Streak differs, so Mundite leaves white, Meta-autunite leaves yellow; luster reads vitreous on Mundite and pearly to dull on Meta-autunite.

How to tell apart: Streak differs, so Mundite leaves white, Phosphuranylite leaves light yellow.

Compare →

Often found alongside mundite

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

All properties

Chemical formula: Al(UO₂)₃(PO₄)₂(OH)₃·5.5H₂O
Mohs hardness: 2-3
Density: 4.295 g/cm³
Colors: Golden yellow Light yellow
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Orthorhombic
Crystal habit: Platy crystals, granular aggregates
Cleavage: Perfect on {010}, {100}, {001}
Rarity: Rare
Uses: Collector
Host rock: A rare mineral in the oxidized uraniferous zone of a complex granite pegmatite

Where rockhounds find mundite

Classic worldwide localities

Kobokobo pegmatite, Lusungu River district, Kivu Province, Congo (Zaire)

Field-hunting tip

Where it forms: A rare mineral in the oxidized uraniferous zone of a complex granite pegmatite. If you start seeing phuralumite, upalite, ranunculite in float, you are in the right ground. Typical habit: platy crystals, granular aggregates. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify mundite?+

Mohs hardness is 2-3. Luster: vitreous. The streak is white. Common colors include golden yellow, light yellow.

Where is mundite found?+

Notable localities include Kobokobo pegmatite, Lusungu River district, Kivu Province, Congo (Zaire).

Is mundite safe to handle?+

Mundite contains uranium or thorium and calls for real care. Mundite is a uranium-bearing mineral and is radioactive; it should be handled with care and stored in a sealed, labeled container in a well-ventilated area.

What rocks look like mundite?+

Mundite is most often confused with Meta-autunite, Phosphuranylite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with mundite?+

Mundite commonly co-occurs with Phuralumite, Upalite, Ranunculite, Threadgoldite, Eylettersite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does mundite form in?+

Where it forms: A rare mineral in the oxidized uraniferous zone of a complex granite pegmatite. Working float back to the host body is the standard way to chase a fresh occurrence.

What is mundite used for?+

Mundite is used in collector.

Find mundite on the map

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