Cobaltkieserite is a rare hydrated cobalt sulfate typically found as an alteration product in cobalt-rich ore deposits. Collectors should look for its distinct pink color in massive or granular forms, often associated with other secondary cobalt minerals.
Is this cobaltkieserite?
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 cobaltkieserite with a known reference. Cobaltkieserite sits at Mohs 2-3, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: pale pink.
- 3Read the lusterHold the specimen under a strong light. Luster: earthy.
- 4Match the color rangeCompare against the expected color range: pink.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: aggregates, powdery, water soluble.
Often confused with
Cobaltkieserite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Cobaltkieserite leaves pale pink, Kieserite leaves white; luster reads earthy on Cobaltkieserite and vitreous on Kieserite.
How to tell apart: Streak differs, so Cobaltkieserite leaves pale pink, Szomolnokite leaves white; luster reads earthy on Cobaltkieserite and vitreous on Szomolnokite.
Often found alongside cobaltkieserite
Minerals reported to co-occur with cobaltkieserite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CoSO₄·H₂O
- Mohs hardness
- 2-3
- Density
- 3.25 g/cm³
- Colors
- Streak
- Pale pink
- Luster
- Earthy
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Aggregates, powdery, water soluble
- Cleavage
- Perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidation products on a museum specimen of copper-cobalt ore collected from the Bastnas deposit
Where rockhounds find cobaltkieserite
Classic worldwide localities
- Bastnas, near Riddarhyttan, Skinnskatteberg, Sweden (type locality)
Field-hunting tip
Where it forms: Oxidation products on a museum specimen of copper-cobalt ore collected from the Bastnas deposit. If you start seeing cobaltite, erythrite, gypsum in float, you are in the right ground. Typical habit: aggregates, powdery, water soluble. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify cobaltkieserite?+
Where is cobaltkieserite found?+
Is cobaltkieserite safe to handle?+
What rocks look like cobaltkieserite?+
What minerals are found with cobaltkieserite?+
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Find cobaltkieserite on the map
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