Jamesonite is a lead-iron sulfosalt prized by collectors for its striking fibrous and hair-like crystal habits. It frequently appears as needle-like sprays or matted aggregates known as 'feather ore' in hydrothermal vein deposits. Due to its lead and antimony content, specimens should be handled with care to avoid ingestion or inhalation of fine particles.
Is this jamesonite?
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 jamesonite with a known reference. Jamesonite sits at Mohs 2.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: black. grayish.
- 3Read the lusterHold the specimen under a strong light. Luster: metallic.
- 4Match the color rangeCompare against the expected color range: lead gray, steel gray, dark lead gray.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: acicular, massive, radial.
Often confused with
Jamesonite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Jamesonite leaves black. grayish, Stibnite leaves lead-gray.
How to tell apart: Streak differs, so Jamesonite leaves black. grayish, Boulangerite leaves brownish.
How to tell apart: Streak differs, so Jamesonite leaves black. grayish, Bournonite leaves steel-gray to iron-black; luster reads metallic on Jamesonite and brilliant to dull on Bournonite.
Often found alongside jamesonite
Minerals reported to co-occur with jamesonite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Pb₄FeSb₆S₁₄
- Mohs hardness
- 2.5
- Density
- 5.63 g/cm³
- Colors
- Streak
- Black. grayish
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Monoclinic
- Crystal habit
- Acicular, massive, radial
- Cleavage
- Good on {001}; reported on {010} and {120}
- Rarity
- Uncommon
- Uses
- Collector
- Host rock
- Typically a late-stage hydrothermal mineral in Pb–Ag–Zn veins formed at low to medium temperatures
Where rockhounds find jamesonite
1 mapped spotsClassic worldwide localities
- Slate Creek, Shoshone Co., Idaho, USA
- Cornwall, England, around St. Endellion (type locality) and St. Kew
- Freiberg, Saxony, Germany
- Magdesprung, Selke Valley, and Clausthal, Harz Mountains, Germany
- Příbram, Czech Republic
- Aranyidka, Baia Sprie (Felsőbánya), and Herja (Kisbánya), Baia Mare (Nagybánya) district, Romania
Field-hunting tip
Where it forms: Typically a late-stage hydrothermal mineral in Pb–Ag–Zn veins formed at low to medium temperatures. If you start seeing pyrite, sphalerite, galena in float, you are in the right ground. Typical habit: acicular, massive, radial. Train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Utah. Start trip planning there.
Common questions
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Find jamesonite on the map
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