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, so Polloneite leaves black, Galena leaves lead-gray.
How to tell apart: Streak differs, so Polloneite leaves black, Bournonite leaves steel-gray.
How to tell apart: Polloneite is noticeably harder (Mohs 3.5 vs. 2.5); streak differs, so 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, 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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