Clausthalite

clausthalite

tiemannite

berzelianite

selenium

Images

Formula: PbSe
Selenide, galena group, a complete solid solution series exists between galena and clausthalite (AM 44.166-175).
Crystal System: Isometric
Specific gravity: 7.8 to 8.22 measured, 8.275 calculated
Hardness: 2½ to 3
Streak: Grey-black
Colour: Bluish grey to lead-grey
Common impurities: Hg,Co,Cu
Environments

Hydrothermal environments

Clausthalite occurs in low-sulphur hydrothermal deposits with other selenides (Webmin) and also in mercury deposits (HOM); it is probably of secondary origin in some deposits (HOM).
Associated minerals include tiemannite, klockmannite, berzelianite, gold, stibiopalladinite, umangite and uraninite (HOM, Mindat).

Localities

At Sierra de Umango, Villa Castelli, General Lamadrid Department, La Rioja Province, Argentina, a massive ore specimen of umangite has been found cut by veinlets of chalcomenite and malachite and having small inclusions of clausthalite (AM 35.337-364).

Also at Sierra de Umango, Villa Castelli, General Lamadrid Department, La Rioja Province, Argentina, a massive ore specimen of klockmannite has been found cut by veinlets of clausthalite and chalcomenite (AM 35.337-364).

At Colquechaca, Colquechaca Municipality, Chayanta Province, Potosí, Bolivia, penroseite has been found cut by veinlets of clausthalite (AM 35.337-364).
Clausthalite from Coquechaca - Image

At Clausthal-Zellerfeld, Goslar District, Lower Saxony, Germany, granular and massive clausthalite has been found embedded in a light silicified rock which contains a few grains of chalcopyrite (AM 35.337-364).
Clausthalite from Clausthal - Image

At the Tilkerode mining district, Mansfeld, Mansfeld-Südharz, Saxony-Anhalt, Germany, clausthalite has been found with chalcopyrite in carbonate gangue (AM 35.337-364).
Clausthalite from Tilkerode - Image

The type locality is the St Lorenz Mine, Clausthal-Zellerfeld, Goslar, Lower Saxony, Germany.

At Tsumeb, Oshikoto Region, Namibia, the little information that is available suggests that clausthalite and umangite may be part of the secondary supergene assemblage rather than the primary hypogene one (R&M 91.6.550).
Clausthalite from Tsumeb - Image

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