Herbertsmithite is a rare copper zinc hydroxychloride that forms distinctive bright green rhombohedral crystals. It is highly sought after by collectors for its significance in quantum physics research as a candidate for a quantum spin liquid. It is typically found as a secondary mineral in oxidized zones of copper deposits.
Is this herbertsmithite?
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 herbertsmithite with a known reference. Herbertsmithite 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. Herbertsmithite leaves a pale green streak.
- 3Read the lusterHold the specimen under a strong light. Herbertsmithite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: bright green, bluish-green.
- 5Look at form & habitCrystal system: trigonal. Typical habit: rhombohedral crystals, fine crusts.
Often confused with
Herbertsmithite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Herbertsmithite leaves pale green, Paratacamite leaves apple green; luster reads vitreous on Herbertsmithite and adamantine on Paratacamite.
How to tell apart: Streak differs, so Herbertsmithite leaves pale green, Atacamite leaves apple green; luster reads vitreous on Herbertsmithite and adamantine to vitreous on Atacamite.
How to tell apart: Streak differs, so Herbertsmithite leaves pale green, Clinoatacamite leaves apple green.
Often found alongside herbertsmithite
Minerals reported to co-occur with herbertsmithite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu₃Zn(OH)₆Cl₂
- Mohs hardness
- 3
- Density
- 4.79 g/cm³
- Colors
- Streak
- Pale Green
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Trigonal
- Crystal habit
- Rhombohedral Crystals, Fine Crusts
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Copper Deposits
- Typical price
- $50-300 per specimen
Where rockhounds find herbertsmithite
Classic worldwide localities
- Chile
- United Kingdom
- United States
- Greece
Field-hunting tip
Look in oxidized copper deposits country, the host setting where herbertsmithite typically forms. If you start seeing paratacamite, atacamite, gerhardtite in float, you are in the right ground. Field specimens usually show a rhombohedral crystals, fine crusts habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find herbertsmithite on the map
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