Natrochalcite is a striking emerald-green secondary mineral typically found in the oxidized zones of copper ore bodies. It most commonly occurs as distinct tabular crystals or as thin, crusty coatings associated with other sulfates in arid climates.
Is this natrochalcite?
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 natrochalcite with a known reference. Natrochalcite sits at Mohs 4.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Natrochalcite leaves a pale green streak.
- 3Read the lusterHold the specimen under a strong light. Natrochalcite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: emerald-green, grass-green, bright green.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: tabular crystals, drusy crusts, fibrous aggregates.
Often confused with
Natrochalcite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Natrochalcite leaves pale green, Brochantite leaves pale-green.
How to tell apart: Natrochalcite is noticeably harder (Mohs 4.5 vs. 3.5); streak differs — Natrochalcite leaves pale green, Antlerite leaves light green.
Often found alongside natrochalcite
Minerals reported to co-occur with natrochalcite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- NaCu₂(SO₄)(OH)₃·H₂O
- Mohs hardness
- 4.5
- Density
- 3.37 g/cm³
- Streak
- Pale Green
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Tabular Crystals, Drusy Crusts, Fibrous Aggregates
- Cleavage
- Perfect On {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Copper Deposits
- Typical price
- $20-200 per specimen depending on size and quality
Where rockhounds find natrochalcite
Classic worldwide localities
- Chuquicamata, Chile
- Sierra Gorda, Chile
- Bingham Canyon, Utah, USA
Field-hunting tip
Look in oxidized copper deposits country — that is the host setting where natrochalcite typically forms. If you start seeing chalcanthite, cuprite, brochantite in float, you are in the right ground. Field specimens usually show a tabular crystals, drusy crusts, fibrous aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find natrochalcite on the map
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