Hermannjahnite is a rare copper-zinc sulfate mineral identified primarily from oxidized ore deposits in Chile. It usually presents as tiny, deep green, equant crystals forming crusts on host rock and is sought after by advanced mineral collectors.
Is this hermannjahnite?
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 hermannjahnite with a known reference. Hermannjahnite sits at Mohs 5-6, 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: white, colorless.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: equant to subhedral crystals, granular aggregates.
Often confused with
Hermannjahnite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Hermannjahnite is noticeably harder (Mohs 5-6 vs. 3.5); streak differs, so Hermannjahnite leaves white, Antlerite leaves pale green.
How to tell apart: Hermannjahnite is noticeably harder (Mohs 5-6 vs. 3.5-4); streak differs, so Hermannjahnite leaves white, Brochantite leaves pale green.
How to tell apart: Hermannjahnite is noticeably harder (Mohs 5-6 vs. 2.5-3); streak differs, so Hermannjahnite leaves white, Langite leaves greenish blue.
Often found alongside hermannjahnite
Minerals reported to co-occur with hermannjahnite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CuZn(SO₄)₂
- Mohs hardness
- 5-6
- Density
- 3.74 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Equant to subhedral crystals, granular aggregates
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- As sublimates around a volcanic fumarole
Where rockhounds find hermannjahnite
Classic worldwide localities
- Chuquicamata mine, Chile
Field-hunting tip
Where it forms: As sublimates around a volcanic fumarole. If you start seeing anhydrite, itelmenite, saranchinaite in float, you are in the right ground. Typical habit: equant to subhedral crystals, granular aggregates. Train your eye for that shape before scanning the outcrop.
Common questions
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What rocks look like hermannjahnite?+
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Find hermannjahnite on the map
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