Cobaltlotharmeyerite is a rare secondary mineral typically found in the oxidation zones of base metal deposits. It is best identified by its distinct orange-to-reddish-brown color and its association with other complex arsenic-bearing minerals in hydrothermal mines.
Is this cobaltlotharmeyerite?
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 cobaltlotharmeyerite with a known reference. Cobaltlotharmeyerite sits at Mohs 4.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: light brown.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: aggregates, fan shaped, lath.
Often confused with
Cobaltlotharmeyerite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Cobaltlotharmeyerite is noticeably harder (Mohs 4.5 vs. ~3); streak differs, so Cobaltlotharmeyerite leaves light brown, Lotharmeyerite leaves pale orange to yellow-orange.
How to tell apart: Streak differs, so Cobaltlotharmeyerite leaves light brown, Tsumcorite leaves yellow.
Often found alongside cobaltlotharmeyerite
Minerals reported to co-occur with cobaltlotharmeyerite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CaCo₂(AsO₄)₂·2H₂O
- Mohs hardness
- 4.5
- Density
- 4.2 g/cm³
- Colors
- Streak
- Light brown
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Aggregates, fan shaped, lath
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In the oxidation zone of polymetallic ore deposits
Where rockhounds find cobaltlotharmeyerite
Classic worldwide localities
- Tsumeb Mine, Namibia
- Bou Azzer, Morocco
Field-hunting tip
Where it forms: In the oxidation zone of polymetallic ore deposits. If you start seeing alumopharmacosiderite, bariumpharmacosiderite, arseniosiderite in float, you are in the right ground. Typical habit: aggregates, fan shaped, lath. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify cobaltlotharmeyerite?+
Where is cobaltlotharmeyerite found?+
Is cobaltlotharmeyerite safe to handle?+
What rocks look like cobaltlotharmeyerite?+
What minerals are found with cobaltlotharmeyerite?+
What kind of rock does cobaltlotharmeyerite form in?+
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Find cobaltlotharmeyerite on the map
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