Jarosewichite is a rare arsenate mineral known primarily from the zinc deposits at Franklin and Sterling Hill, New Jersey. It typically forms small, dark red tabular crystals and is highly prized by advanced mineral collectors for its specific mineral assemblage and unique chemical composition.
Is this jarosewichite?
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 jarosewichite with a known reference. Jarosewichite 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: reddish orange.
- 3Read the lusterHold the specimen under a strong light. Luster: subvitreous on fractured surfaces.
- 4Match the color rangeCompare against the expected color range: dark red.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: tabular crystals.
Often confused with
Jarosewichite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Jarosewichite leaves reddish orange, Holdenite leaves white; luster reads subvitreous on fractured surfaces on Jarosewichite and vitreous on Holdenite.
How to tell apart: Streak differs, so Jarosewichite leaves reddish orange, Chlorophoenicite leaves white; luster reads subvitreous on fractured surfaces on Jarosewichite and vitreous, silky, pearly on cleavages on Chlorophoenicite.
Often found alongside jarosewichite
Minerals reported to co-occur with jarosewichite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Mn₃Mn(AsO₄)(OH)₆
- Mohs hardness
- ~4
- Density
- 3.66 g/cm³
- Colors
- Streak
- Reddish orange
- Luster
- Subvitreous on fractured surfaces
- Transparency
- Translucent through thin edges
- Crystal system
- Orthorhombic
- Crystal habit
- Tabular crystals
- Cleavage
- Perfect basal
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In a mine-dump specimen, incrusting vugs in zinc ore from a metamorphosed stratiform zinc orebody
Where rockhounds find jarosewichite
Classic worldwide localities
- Franklin, Sussex Co., New Jersey, USA
Field-hunting tip
Where it forms: In a mine-dump specimen, incrusting vugs in zinc ore from a metamorphosed stratiform zinc orebody. If you start seeing flinkite, cahnite, allactite in float, you are in the right ground. Typical habit: tabular crystals. Train your eye for that shape before scanning the outcrop.
Common questions
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Find jarosewichite on the map
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