Clausthalite is a rare lead selenide mineral that typically forms as an opaque, lead-gray mass within hydrothermal veins. It is most easily identified by its association with selenium-bearing minerals and its strong metallic luster; it is often found as a minor component in silver or uranium ore deposits.
Is this clausthalite?
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 clausthalite with a known reference. Clausthalite 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. Streak: grayish black.
- 3Read the lusterHold the specimen under a strong light. Luster: metallic.
- 4Match the color rangeCompare against the expected color range: lead gray, blue gray, grayish black.
- 5Look at form & habitCrystal system: cubic. Typical habit: euhedral crystals, granular, massive.
Often confused with
Clausthalite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside clausthalite
Minerals reported to co-occur with clausthalite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- PbSe
- Mohs hardness
- 2.5-3
- Density
- 7.8-8.22 g/cm³
- Streak
- Grayish black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Cubic
- Crystal habit
- Euhedral crystals, granular, massive
- Cleavage
- {001}, good
- Rarity
- Uncommon
- Uses
- Collector, Scientific research
- Host rock
- Associated in low-sulfur hydrothermal deposits with other selenides, also in mercury deposits
Where rockhounds find clausthalite
Classic worldwide localities
- Blue Range Wilderness Area, Greenlee Co., Arizona, USA
- Essex mine, Darwin, Inyo Co., California, USA
- Charlotte mine, Clausthal, 13 km south-southwest of Goslar (type locality), Tilkerode, Lerbach, and Zorge, in the Harz Mountains, and at Schneeberg, Saxony, Germany
- Skrikerum, Sweden
- Hope’s Nose, Torquay, Devon, England
- Bukov, near Tisnova, Czech Republic
Field-hunting tip
Where it forms: Associated in low-sulfur hydrothermal deposits with other selenides, also in mercury deposits. If you start seeing tiemannite, klockmannite, berzelianite in float, you are in the right ground. Typical habit: euhedral crystals, granular, massive. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify clausthalite?+
Where is clausthalite found?+
Is clausthalite safe to handle?+
What rocks look like clausthalite?+
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Find clausthalite on the map
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