Polkovicite is a rare germanium-bearing sulfide mineral that typically occurs as small, brownish gray metallic grains within complex sulfide ore assemblages. It is primarily identified through specialized mineralogical analysis like microprobe testing due to its visual similarity to other dark sulfide minerals. It is famously associated with the unique germanium-rich mineralization found in the Tsumeb Mine.
Is this polkovicite?
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 polkovicite with a known reference. Polkovicite 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. Streak: dark gray.
- 3Read the lusterHold the specimen under a strong light. Luster: metallic.
- 4Match the color rangeCompare against the expected color range: brownish gray.
- 5Look at form & habitCrystal system: cubic. Typical habit: granular to massive.
Often confused with
Polkovicite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside polkovicite
Minerals reported to co-occur with polkovicite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Fe₃GeS₄
- Mohs hardness
- 3.5
- Density
- 6.62 g/cm³
- Colors
- Streak
- Dark gray
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Cubic
- Crystal habit
- Granular to massive
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In epigenetic veinlets and metasomatic replacement zones replacing sandstone and older sulfides, in brecciated sandstones underlying copper-bearing shales
Where rockhounds find polkovicite
Classic worldwide localities
- Polkovice mine, Lower Silesia, Poland
Field-hunting tip
Where it forms: In epigenetic veinlets and metasomatic replacement zones replacing sandstone and older sulfides, in brecciated sandstones underlying copper-bearing shales. If you start seeing marcasite, chalcopyrite, bornite in float, you are in the right ground. Typical habit: granular to massive. Train your eye for that shape before scanning the outcrop.
Common questions
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Find polkovicite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
