Arsenic combines readily with all metals into true arsenides, which latter, in general, are soluble in the metal itself.
It may also be accompanied by pyrites, galena, arsenides and antimonides, quartz, calcite, dolomite, &c. It is widely distributed, and is particularly abundant in Germany (the Harz, Silesia), Austro-Hungary, Belgium, the United States and in England (Cumberland, Derbyshire, Cornwall, North Wales).
According to Herbert Lang, its most prominent chance of success is in localities where fuel is dear, and the ores contain precious metals and sufficient sulphides and arsenides to render profitable dressing unnecessary.
Copper combines directly with arsenic to form several arsenides, some of which occur in the mineral kingdom.
Complex silver minerals (sulph-arsenides and antimonides) which are difficult to amalgamate must be made amenable to quicksilver, and the simplest way of doing this is to convert the silver into chloride.