Ludjibaite is a rare copper phosphate mineral often found as attractive, bright blue, botryoidal or spherulitic crusts in oxidized copper deposits. It is a dimorph of pseudomalachite and is primarily sought after by advanced collectors for its distinctive color and occurrence in the Katanga copper belt.
Is this ludjibaite?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch ludjibaite with a known reference. Ludjibaite sits at Mohs 3.5-4 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Ludjibaite leaves a light blue streak.
- 3Read the lusterHold the specimen under a strong light. Ludjibaite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: blue, greenish-blue.
- 5Look at form & habitCrystal system: triclinic. Typical habit: botryoidal crusts, radiating aggregates, spherulitic.
Often confused with
Ludjibaite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Ludjibaite leaves light blue, Pseudomalachite leaves light green.
How to tell apart: Streak differs — Ludjibaite leaves light blue, Cornetite leaves pale blue.
How to tell apart: Streak differs — Ludjibaite leaves light blue, Libethenite leaves pale green.
Often found alongside ludjibaite
Minerals reported to co-occur with ludjibaite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu₅(PO₄)₂(OH)₄
- Mohs hardness
- 3.5-4
- Density
- 4.25 g/cm³
- Colors
- Streak
- Light Blue
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Triclinic
- Crystal habit
- Botryoidal Crusts, Radiating Aggregates, Spherulitic
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Zones of Copper Ore Deposits
- Typical price
- $50-300 per specimen
Where rockhounds find ludjibaite
Classic worldwide localities
- Ludjiba, Democratic Republic of the Congo
- Katanga Province, Democratic Republic of the Congo
Field-hunting tip
Look in oxidized zones of copper ore deposits country — that is the host setting where ludjibaite typically forms. If you start seeing malachite, pseudomalachite, azurite in float, you are in the right ground. Field specimens usually show a botryoidal crusts, radiating aggregates, spherulitic habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find ludjibaite on the map
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