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 — Herbertsmithite leaves pale green, Paratacamite leaves apple green; luster reads vitreous on Herbertsmithite and adamantine on Paratacamite.
How to tell apart: Streak differs — 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 — 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 — that is 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
How do you identify herbertsmithite?+
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Find herbertsmithite on the map
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