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, so Ludjibaite leaves light blue, Pseudomalachite leaves light green.
How to tell apart: Streak differs, so Ludjibaite leaves light blue, Cornetite leaves pale blue.
How to tell apart: Streak differs, so 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, 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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