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 3.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Polloneite leaves a black streak.
- 3Read the lusterHold the specimen under a strong light. Polloneite typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: lead-gray, black.
- 5Look at form & habitCrystal system: orthorhombic. 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: Polloneite is noticeably harder (Mohs 3.5 vs. 2.5); streak differs — Polloneite leaves black, Galena leaves lead-gray.
How to tell apart: Streak differs — Polloneite leaves black, Bournonite leaves steel-gray.
How to tell apart: Polloneite is noticeably harder (Mohs 3.5 vs. 2.5); streak differs — Polloneite leaves black, Jamesonite leaves gray-black.
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
- Pb₄(As,Sb)₄S₁₁
- Mohs hardness
- 3.5
- Density
- 5.65 g/cm³
- Streak
- Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Orthorhombic
- Crystal habit
- Granular Aggregates, Massive
- Cleavage
- None Observed
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Hydrothermal Veins
- Typical price
- $50-300 per specimen
Where rockhounds find polloneite
Classic worldwide localities
- Pollone mine, Tuscany, Italy
Field-hunting tip
Look in hydrothermal veins country — that is the host setting where polloneite typically forms. If you start seeing galena, sphalerite, pyrite in float, you are in the right ground. Field specimens usually show a granular aggregates, massive habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find polloneite on the map
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