This specimen is from an old miner's collection. Specifically it was collected from the 6850' main ledge at the Homestake. Specimens with this assembladge of minerals are termed "watercourse" minerals, which are Tertiary age open fracture systems sometimes with hot flowing water. It is a typical example with white Calcite rhombic crystals to 3mm, abundant 1mm cubic Pyrite crystals in 5mm clusters, tetrahedrons of black Sphalerite and dull octahedral crystals of pitted Galena. There my also be some Rutile.
As you know, Homestake was the largest producing underground gold mines in the US for quite a while. These days it is the national underground lab seeking dark matter.
