Berzelianite is a rare copper selenide mineral typically found as metallic, grey to silver-white crusts or massive aggregates. It is primarily identified by its association with other rare selenium-bearing minerals in hydrothermal vein deposits. Due to its selenium content, collectors should handle specimens with care and avoid generating dust.
Is this berzelianite?
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 berzelianite with a known reference. Berzelianite sits at Mohs 2.7, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: shining.
- 3Read the lusterHold the specimen under a strong light. Luster: metallic.
- 4Match the color rangeCompare against the expected color range: bluish gray, gray, black.
- 5Look at form & habitCrystal system: cubic. Typical habit: dendritic, disseminated, massive.
Often confused with
Berzelianite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Chalcopyrite is the harder of the two (Mohs 3.5-4 vs. 2.7); streak differs, so Berzelianite leaves shining, Chalcopyrite leaves greenish black.
How to tell apart: Streak differs, so Berzelianite leaves shining, Argentite leaves black.
Often found alongside berzelianite
Minerals reported to co-occur with berzelianite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu₁.₈₈Se
- Mohs hardness
- 2.7
- Density
- 6.71 g/cm³
- Colors
- Streak
- Shining
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Cubic
- Crystal habit
- Dendritic, disseminated, massive
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- With other selenides in hydrothermal veinlets in dolostone (Clausthal, Germany); in iron ores (Lerbach, Germany); with other selenides in calcite veins in serpentine (Skrikerum, Sweden)
Where rockhounds find berzelianite
Classic worldwide localities
- Durant vein, Aurora district, Mineral Co., Nevada, USA
- Skrikerum, near Tryserum, Kalmar, Sweden (type locality)
- Lerbach, Tilkerode, Zorge, Clausthal, and St. Andreasberg, Harz Mountains, Germany
- Niederschlema, Saxony, Germany
- Mullenbach uranium deposit, Black Forest, Germany
- Habrí and Bukov mines, near Tisnova, Czech Republic
Field-hunting tip
Where it forms: With other selenides in hydrothermal veinlets in dolostone (Clausthal, Germany); in iron ores (Lerbach, Germany); with other selenides in calcite veins in serpentine (Skrikerum, Sweden). If you start seeing eucairite, clausthalite, tiemannite in float, you are in the right ground. Typical habit: dendritic, disseminated, massive. Train your eye for that shape before scanning the outcrop.
Common questions
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Find berzelianite on the map
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