Schulenbergite is a rare secondary copper-zinc mineral that typically forms as delicate, pale green platy crystals or thin crusts in oxidized base-metal deposits. It is most commonly found in the weathered zones of mines associated with other copper sulfates and carbonates. Collectors prize it for its distinct, mica-like cleavage and soft, aesthetic color.
Is this schulenbergite?
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 schulenbergite with a known reference. Schulenbergite sits at Mohs ~2, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: blue-green, pale green.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous, pearly on {0001}.
- 4Match the color rangeCompare against the expected color range: green blue, light green blue.
- 5Look at form & habitCrystal system: trigonal. Typical habit: microscopic crystals, rosette.
Often confused with
Schulenbergite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Schulenbergite leaves blue-green, pale green, Langite leaves greenish blue.
How to tell apart: Streak differs, so Schulenbergite leaves blue-green, pale green, Posnjakite leaves pale blue.
How to tell apart: Serpierite is the harder of the two (Mohs 3.5-4 vs. ~2); streak differs, so Schulenbergite leaves blue-green, pale green, Serpierite leaves greenish white.
Often found alongside schulenbergite
Minerals reported to co-occur with schulenbergite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Cu,Zn)₇(SO₄)₂(OH)₁₀·3H₂O
- Mohs hardness
- ~2
- Density
- 3.28-3.42 g/cm³
- Colors
- Green blueLight green blue
- Streak
- Blue-green, pale green
- Luster
- Vitreous, pearly on {0001}
- Transparency
- Transparent
- Crystal system
- Trigonal
- Crystal habit
- Microscopic crystals, rosette
- Cleavage
- Perfect on {0001}; poor on {1120}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A rare secondary mineral formed in the oxidized zone of Cu–Zn-bearing hydrothermal mineral deposits, commonly post-mine; in Cu–Zn slags
Where rockhounds find schulenbergite
Classic worldwide localities
- Harz Mountains, from dumps at the Glücksrad mine, near Oberschulenberg, and in slag at the Ochsenhütte, Granetal, and at Juliushütte, Astfeld, near Goslar, Germany
- Marie mine, southeast of Wilnsdorf, near Siegen, and in the Wilder Mann mine, near Müsen, Siegerland, Germany
- Bastenberg mine, near Ramsbeck, North Rhine-Westphalia, Germany
- Richelsdorfer Mountains, Hesse, Germany
- Dumps of the Friedrichssegen mine, near Bad Ems, at the Virneberg mine, near Rheinbreitbach, Rhineland-Palatinate, Germany
- Cap Garonne mine, near le Pradet, Var, France
Field-hunting tip
Where it forms: A rare secondary mineral formed in the oxidized zone of Cu–Zn-bearing hydrothermal mineral deposits, commonly post-mine; in Cu–Zn slags. If you start seeing namuwite, brochantite, posnjakite in float, you are in the right ground. Typical habit: microscopic crystals, rosette. Train your eye for that shape before scanning the outcrop.
Common questions
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Find schulenbergite on the map
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