Luddenite is a rare lead-copper silicate mineral typically found as delicate, pale green platy crystals or radiating sprays. It is predominantly known from the Mammoth-Saint Anthony Mine in Tiger, Arizona, where it occurs as a secondary mineral in oxidized ore zones.
Is this luddenite?
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 luddenite with a known reference. Luddenite sits at Mohs 2 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Luddenite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Luddenite typically shows a pearly luster.
- 4Match the color rangeCompare against the expected color range: pale green, bluish green.
- 5Look at form & habitCrystal system: triclinic. Typical habit: platy crystals, radial aggregates.
Often confused with
Luddenite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Luster reads pearly on Luddenite and vitreous on Chrysocolla.
How to tell apart: Dioptase is the harder of the two (Mohs 5 vs. 2); streak differs — Luddenite leaves white, Dioptase leaves green; luster reads pearly on Luddenite and vitreous on Dioptase.
Often found alongside luddenite
Minerals reported to co-occur with luddenite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Pb₂Cu₅Si₈O₂₀(OH)₄·10H₂O
- Mohs hardness
- 2
- Density
- 3.37 g/cm³
- Colors
- Streak
- White
- Luster
- Pearly
- Transparency
- Translucent
- Crystal system
- Triclinic
- Crystal habit
- Platy Crystals, Radial Aggregates
- Cleavage
- Perfect On {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Hydrothermal Lead-copper Ore Deposits
- Typical price
- $50-300 per thumbnail specimen
Where rockhounds find luddenite
Classic worldwide localities
- Mammoth-Saint Anthony Mine (Arizona, USA)
Field-hunting tip
Look in oxidized hydrothermal lead-copper ore deposits country — that is the host setting where luddenite typically forms. If you start seeing wulfenite, cerussite, dioptase in float, you are in the right ground. Field specimens usually show a platy crystals, radial aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find luddenite on the map
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