Haydeeite is a rare copper-magnesium chloride mineral occurring in the oxidized zones of copper deposits. It is typically identified by its distinct dark green platy crystals found in association with other copper secondary minerals.
Is this haydeeite?
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 haydeeite with a known reference. Haydeeite 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. Haydeeite leaves a light green streak.
- 3Read the lusterHold the specimen under a strong light. Haydeeite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: dark green, bright green.
- 5Look at form & habitCrystal system: trigonal. Typical habit: platy crystals, granular aggregates.
Often confused with
Haydeeite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Haydeeite leaves light green, Atacamite leaves apple green; luster reads vitreous on Haydeeite and adamantine to vitreous on Atacamite.
How to tell apart: Streak differs — Haydeeite leaves light green, Paratacamite leaves apple green; luster reads vitreous on Haydeeite and adamantine on Paratacamite.
How to tell apart: Streak differs — Haydeeite leaves light green, Botallackite leaves pale green.
Often found alongside haydeeite
Minerals reported to co-occur with haydeeite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu₃Mg(OH)₆Cl₂
- Mohs hardness
- 3
- Density
- 4.26 g/cm³
- Colors
- Streak
- Light Green
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Trigonal
- Crystal habit
- Platy Crystals, Granular Aggregates
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Copper Ore Deposits
- Typical price
- $50-300 per specimen
Where rockhounds find haydeeite
Classic worldwide localities
- Haydee mine, Atacama Province, Chile
Field-hunting tip
Look in oxidized copper ore deposits country — that is the host setting where haydeeite typically forms. If you start seeing gypsum, halite, cuprite in float, you are in the right ground. Field specimens usually show a platy crystals, granular aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find haydeeite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
