Pekoite is a rare lead-copper-bismuth sulfosalt that typically occurs as slender, needle-like crystals within hydrothermal veins. It is most easily recognized in the field as part of a complex suite of bismuth minerals, often requiring X-ray diffraction or chemical analysis for positive identification due to its similarity to other sulfosalts.
Is this pekoite?
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 pekoite with a known reference. Pekoite sits at Mohs 3.5-4 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Pekoite leaves a black streak.
- 3Read the lusterHold the specimen under a strong light. Pekoite typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: lead-gray, steel-gray.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: acicular to prismatic crystals, often as fine needles or radial aggregates.
Often confused with
Pekoite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside pekoite
Minerals reported to co-occur with pekoite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- PbCuBi₁₁S₁₈
- Mohs hardness
- 3.5-4
- Density
- 6.8 g/cm³
- Colors
- Streak
- Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Orthorhombic
- Crystal habit
- Acicular to Prismatic Crystals, Often as Fine Needles or Radial Aggregates
- Cleavage
- Poor
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Hydrothermal Quartz-sulfide Veins
- Typical price
- $50-300 per specimen
Where rockhounds find pekoite
Classic worldwide localities
- Peko Mine, Australia
- Gladhammer, Sweden
- Berezovsk, Russia
- Tasna Mine, Bolivia
Field-hunting tip
Look in hydrothermal quartz-sulfide veins country — that is the host setting where pekoite typically forms. If you start seeing bismutinite, chalcopyrite, gold in float, you are in the right ground. Field specimens usually show a acicular to prismatic crystals, often as fine needles or radial aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find pekoite on the map
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