Pillaite is a rare lead antimony sulfosalt chloride known primarily from the historic mining district of Laurium. It typically forms delicate, needle-like or hair-like crystals found within the cavities of oxidized ore deposits.
Is this pillaite?
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 pillaite with a known reference. Pillaite sits at Mohs 3-4, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: black to dark brown, rare red internal reflections in reflected light.
- 3Read the lusterHold the specimen under a strong light. Luster: metallic.
- 4Match the color rangeCompare against the expected color range: black.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: acicular.
Often confused with
Pillaite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Pillaite leaves black to dark brown, rare red internal reflections in reflected light, Jamesonite leaves black. grayish.
How to tell apart: Streak differs, so Pillaite leaves black to dark brown, rare red internal reflections in reflected light, Boulangerite leaves brownish.
How to tell apart: Streak differs, so Pillaite leaves black to dark brown, rare red internal reflections in reflected light, Plagionite leaves blackish lead-gray, deep red-brown.
Often found alongside pillaite
Minerals reported to co-occur with pillaite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Pb₉Sb₁₀S₂₃ClO₀.₅
- Mohs hardness
- 3-4
- Density
- 5.77 g/cm³
- Colors
- Streak
- Black to dark brown, rare red internal reflections in reflected light
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Monoclinic
- Crystal habit
- Acicular
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Result of complex sulfide deposition by hydrothermal brines, at relatively high temperatures and fO2/fS2 conditions controlled by the pyrite-hematite-magnetite buffer
Where rockhounds find pillaite
Classic worldwide localities
- Buca della Vena mine, Apuan Alps, northern Tuscany, Italy
Field-hunting tip
Where it forms: Result of complex sulfide deposition by hydrothermal brines, at relatively high temperatures and fO2/fS2 conditions controlled by the pyrite-hematite-magnetite buffer. If you start seeing sphalerite, cinnabar, galena in float, you are in the right ground. Typical habit: acicular. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify pillaite?+
Where is pillaite found?+
Is pillaite safe to handle?+
What rocks look like pillaite?+
What minerals are found with pillaite?+
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What is pillaite used for?+
Find pillaite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
