Kolwezite is a rare copper-cobalt carbonate mineral named after its type locality in the Kolwezi mining district. It is typically found as crusts or botryoidal masses in the oxidized zones of copper deposits, often showing a distinctive light to medium green color.
Is this kolwezite?
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 kolwezite with a known reference. Kolwezite 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. Kolwezite leaves a beige streak.
- 3Read the lusterHold the specimen under a strong light. Kolwezite typically shows a pearly luster.
- 4Match the color rangeCompare against the expected color range: blackish brown, pale beige, greenish.
- 5Look at form & habitCrystal system: triclinic. Typical habit: botryoidal, crusts, aggregates of lath-like crystals.
Often confused with
Kolwezite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Kolwezite is noticeably harder (Mohs 3.5-4 vs. 2); streak differs, so Kolwezite leaves beige, Aurichalcite leaves pale blue.
How to tell apart: Streak differs, so Kolwezite leaves beige, Malachite leaves light green; luster reads pearly on Kolwezite and vitreous on Malachite.
How to tell apart: Kolwezite is noticeably harder (Mohs 3.5-4 vs. 2-2.5); streak differs, so Kolwezite leaves beige, Hydrozincite leaves white; luster reads pearly on Kolwezite and dull on Hydrozincite.
Often found alongside kolwezite
Minerals reported to co-occur with kolwezite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Cu,Co)₂(CO₃)(OH)₂
- Mohs hardness
- 3.5-4
- Density
- 3.85 g/cm³
- Streak
- Beige
- Luster
- Pearly
- Transparency
- Translucent
- Crystal system
- Triclinic
- Crystal habit
- Botryoidal, Crusts, Aggregates of Lath-like Crystals
- Cleavage
- Perfect On {010}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Zones of Copper-cobalt Deposits
Where rockhounds find kolwezite
Classic worldwide localities
- Kolwezi, Democratic Republic of the Congo
- Kamoto, Democratic Republic of the Congo
- Shaba Province, Democratic Republic of the Congo
Field-hunting tip
Look in oxidized zones of copper-cobalt deposits country, the host setting where kolwezite typically forms. If you start seeing malachite, heterogenite, chrysocolla in float, you are in the right ground. Field specimens usually show a botryoidal, crusts, aggregates of lath-like crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify kolwezite?+
Where is kolwezite found?+
Is kolwezite safe to handle?+
What rocks look like kolwezite?+
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Find kolwezite on the map
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