Bobkingite is a rare copper chloride hydroxide mineral known primarily from Arizona mines. It typically occurs as small blue or blue-green tabular crystals or thin crusts in oxidized copper zones, often found associated with other copper halide species.
Is this bobkingite?
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 bobkingite with a known reference. Bobkingite 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 blue.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: pale blue.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: microscopic crystals, platy.
Often confused with
Bobkingite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Bobkingite leaves pale blue, Atacamite leaves apple-green; luster reads vitreous on Bobkingite and adamantine to vitreous on Atacamite.
How to tell apart: Streak differs, so Bobkingite leaves pale blue, Paratacamite leaves green.
How to tell apart: Streak differs, so Bobkingite leaves pale blue, Clinoatacamite leaves greenish white; luster reads vitreous on Bobkingite and adamantine to vitreous on Clinoatacamite.
Often found alongside bobkingite
Minerals reported to co-occur with bobkingite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu₅Cl₂(OH)₈·2H₂O
- Mohs hardness
- 3
- Density
- 3.254 g/cm³
- Colors
- Streak
- Pale blue
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Microscopic crystals, platy
- Cleavage
- Perfect on {001} and fair on {100}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In a quarry on crusts of malachite and azurite that overlie massive cuprite in oxidized waste material containing native copper hosted by diorite in a laccolith
Where rockhounds find bobkingite
Classic worldwide localities
- New Cliffe Hill Quarry, Stanton-under-Bardon, Leicestershire, England
Field-hunting tip
Where it forms: In a quarry on crusts of malachite and azurite that overlie massive cuprite in oxidized waste material containing native copper hosted by diorite in a laccolith. If you start seeing malachite, azurite, cuprite in float, you are in the right ground. Typical habit: microscopic crystals, platy. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify bobkingite?+
Where is bobkingite found?+
Is bobkingite safe to handle?+
What rocks look like bobkingite?+
What minerals are found with bobkingite?+
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Find bobkingite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
