Erzwiesite is an incredibly rare sulfosalt mineral primarily known from its type locality in the Gastein Valley of Austria. It typically occurs as small, metallic inclusions within quartz-rich hydrothermal veins associated with other lead and copper-bearing sulfides.
Is this erzwiesite?
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 erzwiesite with a known reference. Erzwiesite sits at Mohs 3-3.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Erzwiesite leaves a black streak.
- 3Read the lusterHold the specimen under a strong light. Erzwiesite typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: lead-gray, black.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: anhedral grains, microscopic inclusions.
Often confused with
Erzwiesite vs. its common look-alikes, and how to tell them apart in the field.

How to tell apart: Streak differs, so Erzwiesite leaves black, Galena leaves lead-gray.


How to tell apart: Erzwiesite is noticeably harder (Mohs 3-3.5 vs. 2); streak differs, so Erzwiesite leaves black, Bismuthinite leaves lead-gray.
Often found alongside erzwiesite
Minerals reported to co-occur with erzwiesite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Pb₃Ag₄Cu₄Bi₁₄S₂₇
- Mohs hardness
- 3-3.5
- Density
- 6.08 g/cm³
- Streak
- Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Monoclinic
- Crystal habit
- Anhedral Grains, Microscopic Inclusions
- Cleavage
- None Observed
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Hydrothermal Quartz Veins
- Typical price
- n/a (extremely rare specimen material)
Where rockhounds find erzwiesite
Classic worldwide localities
- Erzwies, Gastein Valley, Salzburg, Austria
Field-hunting tip
Look in hydrothermal quartz veins country, the host setting where erzwiesite typically forms. If you start seeing galena, quartz, chalcopyrite in float, you are in the right ground. Field specimens usually show a anhedral grains, microscopic inclusions habit, so train your eye for that shape before scanning the outcrop.



