Connellite is a rare, striking copper sulfate chloride mineral that typically forms as delicate, needle-like blue sprays or tufts. It is most famous from the mines of Cornwall, England, where it occurs as a secondary mineral in oxidized copper-rich environments. Collectors value it for its vivid blue color and complex, acicular crystalline habit.
Is this connellite?
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 connellite with a known reference. Connellite sits at Mohs 3, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: pale greenish blue.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: blue green, light blue.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: acicular, fibrous, radial.
Often confused with
Connellite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside connellite
Minerals reported to co-occur with connellite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu₃₆(SO₄)(OH)₆₂Cl₈·6H₂O
- Mohs hardness
- 3
- Density
- 3.36-3.41 g/cm³
- Colors
- Streak
- Pale greenish blue
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Hexagonal
- Crystal habit
- Acicular, fibrous, radial
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- An uncommon secondary mineral in the oxidized portions of copper deposits
Where rockhounds find connellite
Classic worldwide localities
- Grand Central mine, Tintic district, Juab Co. and the Gold Hill mine, Tooele Co., Utah, USA
- Wheals Gorland, Unity, Edward, the Botallack mine, and others in St. Just, England
- Southwick Cliffs, near Dalbeattie, Kirkcudbrightshire, Scotland
- Britannia mine, Snowdonia, Wales
- Cap Garonne mine, near le Pradet, Var, France
- Sa Duchessa mine, Oridda district, Sardinia, Italy
Field-hunting tip
Where it forms: An uncommon secondary mineral in the oxidized portions of copper deposits. If you start seeing cuprite, spangolite, atacamite in float, you are in the right ground. Typical habit: acicular, fibrous, radial. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify connellite?+
Where is connellite found?+
Is connellite safe to handle?+
What rocks look like connellite?+
What minerals are found with connellite?+
What kind of rock does connellite form in?+
What is connellite used for?+
Find connellite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
