Langite is a secondary copper sulfate mineral typically found as attractive sky-blue to blue-green crusts or small tabular crystals in oxidized copper deposits. It is frequently associated with other copper minerals and is best identified by its characteristic color and habit, often requiring careful examination to distinguish from similar species like brochantite.
Is this langite?
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 langite with a known reference. Langite sits at Mohs 2.5-3, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: greenish blue.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous to silky.
- 4Match the color rangeCompare against the expected color range: blue green, green blue, sky blue.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: concretionary, earthy, fibrous.
Often confused with
Langite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside langite
Minerals reported to co-occur with langite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu₄(SO₄)(OH)₆·2H₂O
- Mohs hardness
- 2.5-3
- Density
- 3.28-3.34 g/cm³
- Streak
- Greenish blue
- Luster
- Vitreous to silky
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Concretionary, earthy, fibrous
- Cleavage
- On {001} and {010}
- Rarity
- Uncommon
- Uses
- Collector
- Host rock
- An uncommon but widespread secondary mineral in the oxidation zone of copper sulfide deposits; may be of post-mine formation
Where rockhounds find langite
Classic worldwide localities
- Silver King mine, near Ely, White Pine Co., Nevada, USA
- Grandview mine, Grand Canyon, Coconino Co., and from Bisbee, Cochise Co., Arizona, USA
- Cornwall, from a number of mines, as the Fowey Consols mine, Tywardreath, England
- Botallack mine, St. Just, England
- Bedford United mine, Tavistock, Devon, England
- Engine Vein mine, Alderley Edge, Cheshire, England
Field-hunting tip
Where it forms: An uncommon but widespread secondary mineral in the oxidation zone of copper sulfide deposits; may be of post-mine formation. If you start seeing wroewolfeite, posnjakite, serpierite in float, you are in the right ground. Typical habit: concretionary, earthy, fibrous. Train your eye for that shape before scanning the outcrop.
Common questions
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Find langite on the map
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