Kainotropite is a rare copper iron vanadate that forms iron-black to reddish black prismatic crystals. It is a sublimate at an active volcanic fumarole. It was first described from the Yadovitaya fumarole, Tolbachik Volcano, Kamchatka, Russia.
Is this kainotropite?
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 kainotropite with a known reference. Kainotropite sits at Mohs ~5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: dark brown-red.
- 3Read the lusterHold the specimen under a strong light. Luster: semimetallic.
- 4Match the color rangeCompare against the expected color range: iron-black, reddish black.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: prismatic crystals.
Often confused with
Kainotropite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Kainotropite is noticeably harder (Mohs ~5 vs. 3.5); streak differs, so Kainotropite leaves dark brown-red, Antlerite leaves pale green; luster reads semimetallic on Kainotropite and vitreous on Antlerite.
How to tell apart: Kainotropite is noticeably harder (Mohs ~5 vs. 3.5-4); streak differs, so Kainotropite leaves dark brown-red, Brochantite leaves pale green; luster reads semimetallic on Kainotropite and vitreous, somewhat pearly on cleavages on Brochantite.
Often found alongside kainotropite
Minerals reported to co-occur with kainotropite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu₄Fe³⁺O₂(V₂O₇)(VO₄)
- Mohs hardness
- ~5
- Density
- 4.104 g/cm³
- Colors
- Streak
- Dark brown-red
- Luster
- Semimetallic
- Transparency
- Opaque
- Crystal system
- Orthorhombic
- Crystal habit
- Prismatic crystals
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A sublimate at an active volcanic fumarole
Where rockhounds find kainotropite
Classic worldwide localities
- Yadovitaya fumarole, Second scoria cone, Northern Breakthrough of the Great Tolbachik Fissure Eruption, Tolbachik Volcano, Kamchatka, Russia
Field-hunting tip
Where it forms: A sublimate at an active volcanic fumarole. If you start seeing hematite, langbeinite, calciolangbeinite in float, you are in the right ground. Typical habit: prismatic crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify kainotropite?+
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What rocks look like kainotropite?+
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Find kainotropite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
