Pyrite after Pyrrhotite with Sphalerite

Potosí Mine, Santo Domingo (Francisco Portillo), Santa Eulalia District, Municipio Aquiles Serdán, Chihuahua  Mexico

Specimen size: 3.1 × 1.3 × 1.1 cm = 1.22” × 0.51” × 0.43”
Main crystal size: 2.2 × 0.8 cm = 0.87” × 0.31”