Minerals with the formula MAsS and Mas2 (M = Fe,Ni,Co) are the dominant commercial sources of arsenic, together with REALGAR ( Arsenic Sulfide mineral) & native arsenic.
Arsenopyrite (Fe,As,S) which is related to Iron Pyrite.
Arsenic is recovered as a side product from the purification of Copper.
It is part of the smelter dust from Copper, Gold, & Lead.
Arsenic occurs in many minerals, usually in conjunction with Sulfur & metals.
The main use of metallic arsenic is for strengthening alloys of Copper & especially lead (e.g. in car batteries).
Arsenic is a common N-Type dopant in semiconductor.
Circuits made from Gallium Arsenide (GaAs) are much faster than those made in Silicon. Unlike Silicon, it has a direct band gap, so can be used in laser diodes & LEDs to directly convert electricity into light.
Arsenic is added in small quantities to alpha-brass to make it dezincification-resistant.
“Phosphorus Deoxidized Arsenical Copper” with an arsenic content of 0.3% increased corrosion stability.
