Spangolite is a rare copper sulfate mineral that typically forms distinct, attractive emerald-green tabular or pyramidal crystals. It is most frequently found in the oxidation zones of copper deposits, often occurring as small druses or clusters on a matrix of gossan or associated with other copper minerals.
Is this spangolite?
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 spangolite with a known reference. Spangolite sits at Mohs 2-3, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: pale green.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: dark green, blue green, green, emerald green.
- 5Look at form & habitCrystal system: trigonal. Typical habit: platy, prismatic, tabular.
Often confused with
Spangolite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside spangolite
Minerals reported to co-occur with spangolite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu₆Al(SO₄)(OH)₁₂Cl·3H₂O
- Mohs hardness
- 2-3
- Density
- 3.135-3.141 g/cm³
- Streak
- Pale green
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Trigonal
- Crystal habit
- Platy, prismatic, tabular
- Cleavage
- On {0001}, perfect; distinct on {1011}, {0111}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A rare secondary mineral in the oxidization zone of hydrothermal copper deposits
Where rockhounds find spangolite
Classic worldwide localities
- Copper Queen, Czar, and Southwest mines, Bisbee, Arizona, USA
- Maid of Sunshine mine, Courtland, Turquoise district, Cochise Co., Arizona, USA
- Metcalf, Clifton-Morenci district, Greenlee Co., Arizona, USA
- Mex-Tex, Blanchard, and Portales mines, near Bingham, Hansonburg district, Socorro Co., New Mexico, USA
- Wheal Gorland, Gwennap, and the West Caradon mine, St. Cleer, Cornwall, England
- Trébas, Tarn, and Fontana Rossa, Corsica, France
Field-hunting tip
Where it forms: A rare secondary mineral in the oxidization zone of hydrothermal copper deposits. If you start seeing cuprite, connellite, brochantite in float, you are in the right ground. Typical habit: platy, prismatic, tabular. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify spangolite?+
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What rocks look like spangolite?+
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Find spangolite on the map
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