Karpenkoite is a rare cobalt vanadate, typically orange. Associated minerals include martyite, quartz and gypsum. It was first described from Little Eva mine, Yellow Cat District, Grand County, Utah, USA.
Is this karpenkoite?
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 karpenkoite with a known reference. Karpenkoite 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. Karpenkoite leaves a pale yellow-orange streak.
- 3Read the lusterHold the specimen under a strong light. Karpenkoite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: orange.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: platy crystals, pseudohexagonal scales.
Often confused with
Karpenkoite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Karpenkoite leaves pale yellow-orange, Chrysotile leaves white; luster reads vitreous on Karpenkoite and silky on Chrysotile.
How to tell apart: Streak differs, so Karpenkoite leaves pale yellow-orange, Lizardite leaves white; luster reads vitreous on Karpenkoite and waxy on Lizardite.
How to tell apart: Streak differs, so Karpenkoite leaves pale yellow-orange, Antigorite leaves white; luster reads vitreous on Karpenkoite and resinous to greasy to silky on Antigorite.
Often found alongside karpenkoite
Minerals reported to co-occur with karpenkoite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Co₃(V₂O₇)(OH)₂·2H₂O
- Mohs hardness
- 2-3
- Density
- 3.415 g/cm³
- Colors
- Streak
- Pale Yellow-orange
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Hexagonal
- Crystal habit
- Platy Crystals, Pseudohexagonal Scales
- Cleavage
- Perfect On {0001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Zones of Cobalt-rich Deposits
Where rockhounds find karpenkoite
Classic worldwide localities
- Little Eva mine, Utah, USA
Field-hunting tip
Look in oxidized zones of cobalt-rich deposits country, the host setting where karpenkoite typically forms. If you start seeing quartz, goethite, hematite in float, you are in the right ground. Field specimens usually show a platy crystals, pseudohexagonal scales habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find karpenkoite on the map
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