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Formula: Cu2-xSe (x is approximately 0.12)
Selenide, paramorph of
bellidoite,
berzelianite-umangite group, forms a complete solid-solution series with cubic,
high-temperature
digenite. Selenium-bearing
mineral
Crystal System: Isometric
Specific gravity: 6.71 measured, 7.28 calculated
Hardness: 2
Streak: Shining
Colour: Silver-white, shiny lead-grey; easily tarnishes iridescent blue-grey
Common impurities: Ag,Tl
Environments
Berzelianite occurs with other selenides in hydrothermal veinlets in
dolostone (Webmin). Associated minerals include
eucairite, clausthalite,
tiemannite, umangite,
klockmannite, aguilarite,
crookesite, athabascaite,
stromeyerite, polybasite,
pearceite, gold,
uraninite, pyrite,
marcasite and calcite
(HOM, Mindat).
Localities
At Lake Athabaska, North West Territories, Canada, berzelianite occurs as blebs and veinlets in
calcite gangue associated with umangite
and chalcocite (AM 35.337-364).
At Clausthal, Lower Saxony, Germany, berzelianite occurs with other selenides in hydrothermal veinlets in
dolostone (HOM).
Berzelianite from Clausthal - Image
At Lerbach, Lower Saxony, Germany, berzelianite occurs in iron ores (HOM).
At the type locality, the Skrikerum Mine, Valdemarsvik, Östergötland County, Sweden, berzelianite occurs with
other selenides in calcite veins in
serpentine (HOM, AM 35.337-364).
Berzelianite from Skrikerum - Image
At Redjang-Lebong, Sumatra, berzelianite occurs in a gold -
quartz - orthoclase
deposit (HOM).
At Urora, Nevada, USA, berzelianite is disseminated in a highly weathered siliceous gangue associated with native
gold and lead (AM 35.337-364).
Berzelianite from Urora - Image
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