Arsenopyrite, also known as mispickle, is a silvery-white
mineral with metallic luster, crystallizing in the monoclinic system. Arsenopyrite
is iron sulfarsenide (FeAsS). It is the chief ore of arsenic,
and is found, among other places, in the United States, Canada, Germany,
England, and Scandinavia.
|Arsenopyrite with quartz; specimen
Image source: Wright's Rock Shop, Hot Springs, Arizona
AND PLANETARY SCIENCE