This specimen, from the Homestake mine, is loaded with large 1.5cm anhedral Pyrite and striated, silvery Arsenopyrite crystals showing diamond-shaped outlines and measures up to 6mm and also large massesto 2cm. The matrix is the Homestake Fm, a chloritic schist. It is gold bearing but is not visible. Arsenopyrite when dissolved in HCl will yield tiny bits of Gold.
Arsenopyrite
Formula
FeAsS
Crystal System
Monoclinic
Crystal Habit
Striated, Euhedral Crystals, Prismatic
Cleavage
one distinct
Luster
Metallic
Color
tin white, light steel gray
Streak
black
Geological Setting
Widespread. Most commonly found in medium to high temperature veins.
