Arsenopyrite
“Fool's gold's toxic twin”
Arsenopyrite is an iron arsenic sulfide mineral and the most abundant arsenic-bearing mineral on Earth. It resembles pyrite with its metallic silvery-white luster but is more dangerous — when crushed or heated, it releases toxic arsenic fumes, and its weathering can contaminate groundwater.
iron arsenic sulfide (FeAsS)
Panasqueira (Portugal), Boliden (Sweden), Morro Velho (Brazil), Kalgoorlie (Australia), Freiberg (Germany)
5.5-6
Gold frequently hides locked inside arsenopyrite crystals — a phenomenon called 'refractory gold' that makes extraction so difficult it requires special roasting or bacterial processing techniques.
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What is 'refractory gold' and why does arsenopyrite make it so difficult to extract?
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