Caryinite is a rare arsenic-bearing mineral typically found as massive or granular aggregates in metamorphosed manganese deposits. It is most famous for its association with the classic Långban mining district in Sweden, where it occurs within complex skarn assemblages.
Is this caryinite?
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 caryinite with a known reference. Caryinite sits at Mohs 4, 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: greasy.
- 4Match the color rangeCompare against the expected color range: brown, yellow brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: cleaveable, massive.
Often confused with
Caryinite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Alluaudite is the harder of the two (Mohs 5-5.5 vs. 4); streak differs, so Caryinite leaves light brown, Alluaudite leaves dirty yellow; luster reads greasy on Caryinite and vitreous to resinous on Alluaudite.
How to tell apart: Adelite is the harder of the two (Mohs 5 vs. 4); streak differs, so Caryinite leaves light brown, Adelite leaves white; luster reads greasy on Caryinite and resinous on Adelite.
How to tell apart: Caryinite is noticeably harder (Mohs 4 vs. ~3); streak differs, so Caryinite leaves light brown, Cahnite leaves white; luster reads greasy on Caryinite and vitreous on Cahnite.
Often found alongside caryinite
Minerals reported to co-occur with caryinite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- NaCaCaMn₂(AsO₄)₃
- Mohs hardness
- 4
- Density
- 4.29 g/cm³
- Colors
- Streak
- Light brown
- Luster
- Greasy
- Transparency
- Subtranslucent
- Crystal system
- Monoclinic
- Crystal habit
- Cleaveable, massive
- Cleavage
- On {110} and {010}, distinct
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In veinlets in skarn in a metamorphosed Fe–Mn orebody
Where rockhounds find caryinite
Classic worldwide localities
- Långban, Värmland, Sweden
Field-hunting tip
Where it forms: In veinlets in skarn in a metamorphosed Fe–Mn orebody. If you start seeing berzeliite, adelite, hedyphane in float, you are in the right ground. Typical habit: cleaveable, massive. Train your eye for that shape before scanning the outcrop.
Common questions
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Find caryinite on the map
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