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. Connellite leaves a pale blue streak.
- 3Read the lusterHold the specimen under a strong light. Connellite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: bright blue, azure blue, deep blue.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: acicular or fibrous radial sprays, prismatic crystals.
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
- Cu₁₉(SO₄)(OH)₃₂Cl₄·3H₂O
- Mohs hardness
- 3
- Density
- 3.4-3.5 g/cm³
- Streak
- Pale Blue
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Hexagonal
- Crystal habit
- Acicular or Fibrous Radial Sprays, Prismatic Crystals
- Cleavage
- Good On {10-10}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Copper Ore Deposits
- Typical price
- $20-150 thumbnail, $200+ cabinet specimen
Where rockhounds find connellite
Classic worldwide localities
- Cornwall, England
- Bisbee, Arizona, USA
- Tsumeb, Namibia
- Chuquicamata, Chile
Field-hunting tip
Look in oxidized copper ore deposits country — that is the host setting where connellite typically forms. If you start seeing cuprite, malachite, brochantite in float, you are in the right ground. Field specimens usually show a acicular or fibrous radial sprays, prismatic crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find connellite on the map
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