Magnetite (variety martite) on matrix

Payún Matru Volcano, Malargüe, Malargüe Department, Mendoza Province  Argentina (2008)

Specimen size: 8 × 6.6 × 5 cm = 3.15” × 2.60” × 1.97”
Main crystal size: 2.8 × 1.6 cm = 1.10” × 0.63”