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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
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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