Jôkokuite is a rare manganese sulfate mineral typically found in weathered hydrothermal deposits. It is best identified by its pale pink color and occurrence as a secondary mineral in manganese-rich environments, often forming as crusts or granular aggregates.
Is this jôkokuite?
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 jôkokuite with a known reference. Jôkokuite sits at Mohs ~2.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: light pink.
- 5Look at form & habitCrystal system: triclinic. Typical habit: granular, massive, or encrustations.
Often confused with
Jôkokuite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside jôkokuite
Minerals reported to co-occur with jôkokuite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- MnSO₄·5H₂O
- Mohs hardness
- ~2.5
- Density
- 2.03 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent to translucent
- Crystal system
- Triclinic
- Crystal habit
- Granular, massive, or encrustations
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- As efflorescences in oxidized portions of mine workings, apparently deposited from mine waters at 25°C
Where rockhounds find jôkokuite
Classic worldwide localities
- Jokoku and Inakuraishi mines, Hokkaido, Japan
- Chvaletice, Czech Republic
Field-hunting tip
Where it forms: As efflorescences in oxidized portions of mine workings, apparently deposited from mine waters at 25°C. If you start seeing gypsum, szmikite, ilesite in float, you are in the right ground. Typical habit: granular, massive, or encrustations. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify jôkokuite?+
Where is jôkokuite found?+
What rocks look like jôkokuite?+
What minerals are found with jôkokuite?+
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What is jôkokuite used for?+
Find jôkokuite on the map
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