Goudeyite is a rare copper-aluminum arsenate mineral that typically forms vibrant, needle-like tufts or crusts in oxidized copper zones. It is highly sought after by micromounters and mineral collectors due to its intense color and delicate crystal habits, often appearing as distinct yellow-green or green sprays.
Is this goudeyite?
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 goudeyite with a known reference. Goudeyite sits at Mohs 3-4 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Goudeyite leaves a pale yellow streak.
- 3Read the lusterHold the specimen under a strong light. Goudeyite typically shows a vitreous to adamantine luster.
- 4Match the color rangeCompare against the expected color range: yellow, yellowish-green, bright green.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: acicular or tufted crusts.
Often confused with
Goudeyite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside goudeyite
Minerals reported to co-occur with goudeyite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu₆Al(AsO₄)₃(OH)₆·3H₂O
- Mohs hardness
- 3-4
- Density
- 4.2-4.5 g/cm³
- Streak
- Pale Yellow
- Luster
- Vitreous to Adamantine
- Transparency
- Translucent
- Crystal system
- Hexagonal
- Crystal habit
- Acicular or Tufted Crusts
- Cleavage
- None Observed
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Hydrothermal Copper-arsenic Ore Deposits
- Typical price
- $50-300 per specimen depending on size and quality
Where rockhounds find goudeyite
Classic worldwide localities
- Majuba Hill Mine, Nevada, USA
- Tsumeb Mine, Namibia
- Ojuela Mine, Mexico
Field-hunting tip
Look in oxidized hydrothermal copper-arsenic ore deposits country — that is the host setting where goudeyite typically forms. If you start seeing olivenite, clinoclase, conichalcite in float, you are in the right ground. Field specimens usually show a acicular or tufted crusts habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find goudeyite on the map
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