Boulangerite is a lead antimony sulfosalt typically found as feathery or hair-like aggregates that give rise to its alternative name, plumosite. Collectors should look for its distinct metallic luster and brittle, fibrous habit when inspecting specimens from hydrothermal ore deposits.
Is this boulangerite?
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 boulangerite with a known reference. Boulangerite sits at Mohs 2.5-3 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Boulangerite leaves a brownish-gray streak.
- 3Read the lusterHold the specimen under a strong light. Boulangerite typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: lead-gray, bluish-gray.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: acicular crystals, fibrous, plumose, or massive.
Often confused with
Boulangerite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Boulangerite leaves brownish-gray, Jamesonite leaves gray-black.
How to tell apart: Streak differs — Boulangerite leaves brownish-gray, Stibnite leaves lead-gray.
How to tell apart: Streak differs — Boulangerite leaves brownish-gray, Bournonite leaves steel-gray.
Often found alongside boulangerite
Minerals reported to co-occur with boulangerite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Pb₅Sb₄S₁₁
- Mohs hardness
- 2.5-3
- Density
- 6.2-6.3 g/cm³
- Colors
- Streak
- Brownish-gray
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Monoclinic
- Crystal habit
- Acicular Crystals, Fibrous, Plumose, Or Massive
- Cleavage
- Good in One Direction
- Rarity
- Uncommon
- Uses
- Collector, Ore of Lead
- Host rock
- Hydrothermal Veins
- Typical price
- $15-150 depending on specimen size and crystal quality
Where rockhounds find boulangerite
Classic worldwide localities
- France
- Germany
- Czech Republic
- Canada
- USA
Field-hunting tip
Look in hydrothermal veins country — that is the host setting where boulangerite typically forms. If you start seeing galena, siderite, pyrite in float, you are in the right ground. Field specimens usually show a acicular crystals, fibrous, plumose, or massive habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find boulangerite on the map
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