Polloneite is a rare lead-arsenic sulfosalt primarily known from the Pollone mine in Italy. It typically presents as metallic lead-gray to black granular masses associated with other base metal sulfides in hydrothermal deposits.
Is this polloneite?
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 polloneite with a known reference. Polloneite sits at Mohs 3-3.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: black.
- 3Read the lusterHold the specimen under a strong light. Luster: metallic.
- 4Match the color rangeCompare against the expected color range: grayish black.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: granular aggregates, massive.
Often confused with
Polloneite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Polloneite leaves black, Galena leaves lead-gray.
How to tell apart: Streak differs, so Polloneite leaves black, Bournonite leaves steel-gray to iron-black; luster reads metallic on Polloneite and brilliant to dull on Bournonite.
How to tell apart: Streak differs, so Polloneite leaves black, Jamesonite leaves black. grayish.
Often found alongside polloneite
Minerals reported to co-occur with polloneite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- AgPb₄₆As₂₆Sb₂₃S₁₂₀
- Mohs hardness
- 3-3.5
- Density
- 5.77 g/cm³
- Colors
- Streak
- Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Monoclinic
- Crystal habit
- Granular aggregates, massive
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In a hydrothermal vein barite-pyrite-(Pb-Zn-Ag) deposit
Where rockhounds find polloneite
Classic worldwide localities
- Pizzone level, Pollone mine, Valdicastello Carducci, near Pietrasanta, Apuan Alps, Tuscany, Italy
Field-hunting tip
Where it forms: In a hydrothermal vein barite-pyrite-(Pb-Zn-Ag) deposit. If you start seeing barite in float, you are in the right ground. Typical habit: granular aggregates, massive. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify polloneite?+
Where is polloneite found?+
Is polloneite safe to handle?+
What rocks look like polloneite?+
What minerals are found with polloneite?+
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Find polloneite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
