Seeligerite is a very rare lead iodate mineral primarily known from the oxidized zones of lead deposits in Chile. It typically forms small, vibrant yellow, tabular crystals that possess a distinct adamantine luster. Collectors prize it for its unique chemistry and exceptional rarity, usually occurring in small, delicate clusters.
Is this seeligerite?
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 seeligerite with a known reference. Seeligerite sits at Mohs 2.5-3, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: light yellow.
- 3Read the lusterHold the specimen under a strong light. Luster: adamantine.
- 4Match the color rangeCompare against the expected color range: light yellow.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: platy.
Often confused with
Seeligerite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Seeligerite leaves light yellow, Wulfenite leaves white; luster reads adamantine on Seeligerite and resinous, subadamantine to adamantine on Wulfenite.
How to tell apart: Streak differs, so Seeligerite leaves light yellow, Anglesite leaves white.
Often found alongside seeligerite
Minerals reported to co-occur with seeligerite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Pb₃Cl₃(IO₃)O
- Mohs hardness
- 2.5-3
- Density
- 6.83 g/cm³
- Colors
- Streak
- Light yellow
- Luster
- Adamantine
- Transparency
- Semitransparent
- Crystal system
- Orthorhombic
- Crystal habit
- Platy
- Cleavage
- Good on {001}, {110}; poor on {100}, {010}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A rare secondary mineral formed in the oxidized zone of hydrothermal polymetallic mineral deposits
Where rockhounds find seeligerite
Classic worldwide localities
- Santa Ana, Casucha, and San Francisco (Beatriz) mines, near Caracoles, Sierra Gorda district, Antofagasta, Chile
Field-hunting tip
Where it forms: A rare secondary mineral formed in the oxidized zone of hydrothermal polymetallic mineral deposits. If you start seeing boleite, paralaurionite, schwartzembergite in float, you are in the right ground. Typical habit: platy. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify seeligerite?+
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Is seeligerite safe to handle?+
What rocks look like seeligerite?+
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Find seeligerite on the map
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